Set based camlib definition and --with-camlibs handlingissue-467-wip4

This uses proper set operations both for GP_CAMLIB and for handling
the --with-camlibs value. This allows all GP_CAMLIB definitions to
be present at autoreconf time (as m4 code) time but some being
conditional at the time of the configure run (in the sh code).

The ./configure output is still a bit verbose, but we can reduce that
verbosity later when we have found out that this works well on people's
different systems.

Fixes: https://github.com/gphoto/libgphoto2/issues/467

7 files changed, 1384 insertions, 205 deletions

diff --git a/camlibs/Makefile.am b/camlibs/Makefile.am
index c6a6e257a..34926281a 100644
--- a/camlibs/Makefile.am
+++ b/camlibs/Makefile.am
@@ -6,8 +6,8 @@
 # or
 #     ( cd camlibs && make agfa_cl20.la )
 #
-# If you only want to install a single camlib or two, run
-#     make BUILD_THESE_CAMLIBS="canon.la agfa_cl20.la" install
+# If you only want to build/install a single camlib or two, run
+#     make GP_CAMLIB_SET="canon.la agfa_cl20.la" install
 # in the camlibs/ subdir or in the libgphoto2 top-level directory.
 ########################################################################
 
@@ -35,6 +35,18 @@ EXTRA_LTLIBRARIES =
 
 
 ########################################################################
+# We pass the list of camlibs through this set of variables in order
+# to remain compatible with older calling conventions.
+
+# Actually implement BUILD_THESE_CAMLIBS as documented
+BUILD_THESE_CAMLIBS = $(GP_CAMLIB_SET)
+
+# while keeping compatibility with the variable which has been working
+# for so long
+INSTALL_THESE_CAMLIBS = $(BUILD_THESE_CAMLIBS)
+
+
+########################################################################
 # All camlibs are defined as EXTRA_LTLIBRARIES. This requires that
 # all camlibs have -rpath set explicitly in foobar_la_LDFLAGS.
 # You're probably best off by using the camlib_* variables defined
@@ -46,17 +58,29 @@ camlib_LTLIBRARIES = $(INSTALL_THESE_CAMLIBS)
 # Define the compile/link/etc. flags common to all camlibs in one place,
 # i.e. here.
 
-camlib_dependencies = $(top_srcdir)/camlibs/camlib.sym
-camlib_ldflags = -module -no-undefined -avoid-version -export-dynamic \
-	-export-symbols '$(top_srcdir)/camlibs/camlib.sym' \
-	-rpath '$(camlibdir)'
-camlib_libadd = $(top_builddir)/libgphoto2/libgphoto2.la $(top_builddir)/libgphoto2_port/libgphoto2_port/libgphoto2_port.la 
+camlib_dependencies =
+camlib_dependencies += $(top_srcdir)/camlibs/camlib.sym
+
+camlib_ldflags =
+camlib_ldflags += -module
+camlib_ldflags += -no-undefined
+camlib_ldflags += -avoid-version
+camlib_ldflags += -export-dynamic
+camlib_ldflags += -export-symbols '$(top_srcdir)/camlibs/camlib.sym'
+camlib_ldflags += -rpath '$(camlibdir)'
+
+camlib_libadd =
+camlib_libadd += $(top_builddir)/libgphoto2/libgphoto2.la
+camlib_libadd += $(top_builddir)/libgphoto2_port/libgphoto2_port/libgphoto2_port.la
+
+AM_CPPFLAGS += -I$(top_srcdir) -I$(top_builddir)
+AM_CPPFLAGS += -I$(top_srcdir)/libgphoto2_port
+AM_CPPFLAGS += -I$(top_srcdir)/libgphoto2 -I$(top_builddir)/libgphoto2
 
-AM_CPPFLAGS += -I$(top_srcdir) -I$(top_builddir)  -I$(top_srcdir)/libgphoto2_port -I$(top_srcdir)/libgphoto2 -I$(top_builddir)/libgphoto2
 
 ########################################################################
 # You can generate this Makefile-files include list by running
-# find . -name Makefile-files -exec echo include {} \; | sort | sed 's| ./| |g' 
+# find . -name Makefile-files -exec echo include {} \; | sort | sed 's| ./| |g'
 include adc65/Makefile-files
 include agfa-cl20/Makefile-files
 include aox/Makefile-files
@@ -136,17 +160,33 @@ print-camlibs: Makefile
 # Make sure that the list of camlibs defined in configure.ac using
 # GP_CAMLIB(...) and the list of camlibs defined in */Makefile-files
 # match.
-CLEANFILES += all-src-camlibs all-def-camlibs
-all-local: Makefile
-	@:; \
-	(for x in $(EXTRA_LTLIBRARIES) template.la; do echo "$$(basename "$$x" ".la")"; done) \
-		| sort > all-src-camlibs; \
-	(for x in $(ALL_DEFINED_CAMLIBS); do echo "$$x"; done) \
-		| sort > all-def-camlibs; \
-	if cmp all-def-camlibs all-src-camlibs; then :; else \
-		diff -u all-def-camlibs all-src-camlibs; \
-		echo "List of camlibs in configure.ac is out of date."; \
-		echo "Have a developer update it using \"make -C camlibs print-camlibs\"."; \
+
+# List all camlibs defined in configure.ac
+CLEANFILES += all-cfg-camlibs
+all-cfg-camlibs: Makefile
+	@(for x in $(GP_CAMLIB_SET_EVERYTHING); do echo "$$x"; done) \
+		| LC_ALL=C $(SORT) > all-cfg-camlibs
+
+# List all camlibs defined in the camlibs/ source subtree Makefile-files
+CLEANFILES += all-mkf-camlibs
+all-mkf-camlibs: Makefile
+	@(for x in $(EXTRA_LTLIBRARIES) $(noinst_LTLIBRARIES); do echo "$$(basename "$$x" ".la")"; done) \
+		| LC_ALL=C $(SORT) > all-mkf-camlibs
+
+.PHONY: all-local
+all-local: all-cfg-camlibs all-mkf-camlibs
+	@if $(CMP) all-cfg-camlibs all-mkf-camlibs > /dev/null 2>&1; then :; else \
+		echo "#"; \
+		for camlib in $$($(COMM) -23 all-cfg-camlibs all-mkf-camlibs); do \
+			echo "#   - '$${camlib}' camlib in 'configure.ac', but not in Makefiles."; \
+		done; \
+		for camlib in $$($(COMM) -13 all-cfg-camlibs all-mkf-camlibs); do \
+			echo "#   - '$${camlib}' camlib in Makefiles, but not in 'configure.ac'"; \
+		done; \
+		echo "#"; \
+		echo "# The camlib set definitions in 'configure.ac' and Makefiles are inconsistent"; \
+		echo "# Have a developer sync them, maybe using \"make -C camlibs print-camlibs\"."; \
+		echo "#"; \
 		exit 1; \
 	fi
 
@@ -155,8 +195,8 @@ all-local: Makefile
 # Shortcut for installation of a subset of camlibs
 # Usage: make CAMLIBS="canon.la ptp2.la" install-camlibs
 
-install-camlibs:
-	$(MAKE) $(AM_MAKEFLAGS) BUILD_THESE_CAMLIBS="$(CAMLIBS)" install-camlibLTLIBRARIES
+install-camlibs: $(GP_CAMLIB_SET)
+	$(MAKE) $(AM_MAKEFLAGS) GP_CAMLIB_SET="$(GP_CAMLIB_SET)" install-camlibLTLIBRARIES
 
 
 ########################################################################
diff --git a/camlibs/lumix/lumix.c b/camlibs/lumix/lumix.c
index 3115b0648..5cb8ee450 100644
--- a/camlibs/lumix/lumix.c
+++ b/camlibs/lumix/lumix.c
@@ -27,17 +27,13 @@
 
 #include <string.h>
 #include <errno.h>
-#ifdef HAVE_LIBCURL
-# include <curl/curl.h>
-#endif
+#include <curl/curl.h>
 #include <stdio.h>
 #include <stdlib.h>
-#ifdef HAVE_LIBXML2
-# include <libxml/parser.h>
-# include <libxml/tree.h>
-# include <libxml/xmlmemory.h>
-# include <libxml/xmlreader.h>
-#endif
+#include <libxml/parser.h>
+#include <libxml/tree.h>
+#include <libxml/xmlmemory.h>
+#include <libxml/xmlreader.h>
 
 
 #include <sys/socket.h>
@@ -87,7 +83,6 @@
 #  define N_(String) (String)
 #endif
 
-#if defined(HAVE_LIBCURL) && defined(HAVE_LIBXML2)
 
 char* CDS_Control  = ":60606/Server0/CDS_control";
 int ReadoutMode = 2; // this should be picked up from the settings.... 0-> JPG; 1->RAW; 2 -> Thumbnails
@@ -1919,19 +1914,6 @@ camera_init (Camera *camera, GPContext *context)
 		return GP_ERROR_IO;
 }
 
-#else
-/* no XML2 or no CURL -> no camera here */
-int
-camera_init (Camera *camera, GPContext *context) 
-{
-	return GP_OK;
-}
-
-int camera_abilities (CameraAbilitiesList *list)
-{
-	return GP_OK;
-}
-#endif
 
 int
 camera_id (CameraText *id) 
diff --git a/configure.ac b/configure.ac
index 7b7bd7f24..e2839ca86 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 dnl Process this file with autoreconf to produce a configure script.
-AC_PREREQ(2.59)
+AC_PREREQ(2.62)
 
 dnl NOTE: Be version style _higher_ than the last release.
 dnl       So lastversion.X.trunk for instance. Bump X if necessary.
@@ -255,6 +255,13 @@ AC_CHECK_LIB(m, sqrt)
 
 
 dnl ---------------------------------------------------------------------------
+dnl test GP_SET_ macros from gp-set.m4
+dnl ---------------------------------------------------------------------------
+dnl GP_SET_TESTSUITE
+dnl AC_MSG_ERROR([gp-set.m4 testsuite done.])
+
+
+dnl ---------------------------------------------------------------------------
 dnl check for libjpeg
 dnl ---------------------------------------------------------------------------
 LIBJPEG=""
@@ -289,7 +296,11 @@ GP_CHECK_LIBRARY([LIBCURL],[libcurl],[>= 7.1],
 )
 GP_CONFIG_MSG([CURL support for Lumix Wifi],[${have_LIBCURL}])
 
-AM_CONDITIONAL([BUILD_LUMIX], [test -n "$have_LIBCURL" && test "X$have_LIBCURL" != "Xno" && test -n "$have_LIBXML2" && test "X$have_LIBXML2" != "Xno"])
+AM_CONDITIONAL([HAVE_LIBCURL],
+               [test -n "$have_LIBCURL" && test "X$have_LIBCURL" != "Xno"])
+AM_CONDITIONAL([HAVE_LIBXML2],
+               [test -n "$have_LIBXML2" && test "X$have_LIBXML2" != "Xno"])
+
 
 dnl ---------------------------------------------------------------------------
 dnl check for libgd
@@ -476,13 +487,15 @@ AM_CPPFLAGS="$AM_CPPFLAGS -DCAMLIBS=\\\"\$(camlibdir)\\\""
 dnl ---------------------------------------------------------------------------
 dnl Camera drivers (camlibs)
 dnl ---------------------------------------------------------------------------
-dnl * See m4m/gp-camlibs.m4 for usage details, e.g. for marking camlibs as
+dnl * See gp-camlibs.m4 for usage details, e.g. for marking camlibs as
 dnl   unlisted.
 dnl * Please add new camlibs in alphabetical order.
 dnl * Selective build:
 dnl   $ make -C camlibs canon.la ptp2.la
+dnl   or
+dnl   $ make -C camlibs GP_CAMLIB_SET="canon.la ptp2.la"
 dnl * Selective install:
-dnl   $ make CAMLIBS="canon.la ptp2.la" install-camlibs
+dnl   $ make GP_CAMLIB_SET="canon.la ptp2.la" install-camlibs
 GP_CAMLIB([adc65],[outdated])dnl very old serial camera
 GP_CAMLIB([agfa_cl20],[outdated])dnl
 GP_CAMLIB([aox],[outdated])dnl
@@ -513,7 +526,11 @@ GP_CAMLIB([konica],[outdated])dnl
 GP_CAMLIB([konica_qm150],[outdated])dnl
 GP_CAMLIB([largan],[outdated])dnl
 GP_CAMLIB([lg_gsm],[outdated])dnl
+AM_COND_IF([HAVE_LIBCURL], [dnl
+AM_COND_IF([HAVE_LIBXML2], [dnl
 GP_CAMLIB([lumix])dnl
+])
+])
 GP_CAMLIB([mars])dnl
 GP_CAMLIB([dimagev])dnl
 GP_CAMLIB([mustek],[outdated])dnl
@@ -552,7 +569,6 @@ GP_CAMLIB([toshiba_pdrm11],[outdated])dnl
 GP_CAMLIB([tp6801])dnl
 dnl
 GP_CAMLIBS_DEFINE()dnl
-GP_CONFIG_MSG([Camlibs],[${camlibs}])
 
 
 dnl --------------------------------------------------------------------
@@ -626,13 +642,21 @@ if test -d "$srcdir/libgphoto2_port"; then
 	AC_CONFIG_SUBDIRS([libgphoto2_port])
 else
 	AC_MSG_ERROR([
-*** Hey, where have you hidden my libgphoto2_port?
-*** I needed that!
+******************************************************
+*** Hey, where have you hidden my libgphoto2_port? ***
+*** I needed that!                                 ***
+******************************************************
 ])
 fi
 
 
 # ---------------------------------------------------------------------------
+# clean up
+# ---------------------------------------------------------------------------
+GP_SET_CLEAN_FILES
+
+
+# ---------------------------------------------------------------------------
 # Create output files
 # ---------------------------------------------------------------------------
 AC_CONFIG_FILES([
@@ -662,11 +686,13 @@ doc/api/Makefile
 ],[
 dnl This relies on this code being called for each of the above files
 dnl with ac_file set to the filename.
-	if echo "$ac_file" | grep '.sh$' > /dev/null; then
-		if test -f "$ac_file"; then
-			chmod +x "$ac_file"
-		fi
+case "$ac_file" in #(
+*.sh)
+	if test -f "$ac_file"; then
+		chmod +x "$ac_file"
 	fi
+	;;
+esac
 ])
 AC_OUTPUT
 
@@ -685,11 +711,7 @@ GP_CONFIG_OUTPUT
 dnl Catch the Gentoo folks about to shoot themselves in the foot.
 dnl Just enabling "foo" often does not make a camera made by
 dnl manufacturer "Foo" work.
-if test "x$camlibs" = "xall"; then
-   :
-else
-   GP_CAMLIBS_WARNING
-fi
+GP_CAMLIBS_CONDITIONAL_WARNING
 
 cat<<_GP_EOF
 Please check whether the configuration I have detected matches what
diff --git a/gphoto-m4/gp-camlibs.m4 b/gphoto-m4/gp-camlibs.m4
index a7c82fe97..c798b4f71 100644
--- a/gphoto-m4/gp-camlibs.m4
+++ b/gphoto-m4/gp-camlibs.m4
@@ -1,191 +1,476 @@
+dnl ####################################################################
+dnl
 dnl GP_CAMLIB & Co.
 dnl
+dnl ####################################################################
+dnl
 dnl Redundancy free definition of libgphoto2 camlibs.
 dnl
 dnl Removes the redundany from the camlib lists, and executes
-dnl additional consistency checks, e.g. to ensure that subdirectories
-dnl actually exist.
+dnl additional consistency checks on the build system.
+dnl
+dnl Every camlib belongs to one of the following (disjunct) sets of
+dnl camlibs:
+dnl
+dnl   * the 'standard' set
 dnl
-dnl You can mark camlibs as unlisted, i.e. they won't be listed
-dnl explicitly but still be recognized.
+dnl     The set of camlibs which is most likely to support the most
+dnl     cameras. This is the default when --with-camlibs=... is not
+dnl     given. This used to be called 'all', even though it
+dnl     definitively does not comprise all camlibs.
+dnl
+dnl   * the 'outdated' set
+dnl
+dnl     These cameras are outdated in some way. The cameras may have
+dnl     fallen out of use, the camlib might have been superseded by
+dnl     another one, or other reasons. Not built by default.
+dnl
+dnl   * the 'unlisted' set
+dnl
+dnl     These camlibs will not be listed by './configure --help', but
+dnl     they can still be added to the set of camlibs to be built.
 dnl
 dnl Example usage:
 dnl
 dnl   GP_CAMLIB([canon])
 dnl   GP_CAMLIB([casio])
 dnl   [...]
+dnl   AM_COND_IF([HAVE_LIBCURL], [dnl
+dnl   AM_COND_IF([HAVE_LIBXML2], [dnl
+dnl     GP_CAMLIB([lumix])dnl
+dnl   ])
+dnl   ])
+dnl   [...]
 dnl   GP_CAMLIB([ptp],[unlisted])
 dnl   GP_CAMLIB([ptp2])
 dnl   [...]
 dnl   GP_CAMLIB([toshiba])
-dnl   GP_CAMLIBS_DEFINE([camlibs])
+dnl   GP_CAMLIBS_DEFINE()
 dnl
-dnl The camlibs basedir parameter of GP_CAMLIBS_DEFINE is optional.
 dnl
 dnl ####################################################################
+dnl Implementation remarks
+dnl ####################################################################
+dnl
+dnl Note that at this time, the set names are hard coded, but could be
+dnl moved to a m4 time automatic set of set names at a later time.
+dnl
+dnl A few notes on macro and variable naming:
+dnl
+dnl   * GP_* are the macros to be called from configure.ac
+dnl   * GP_CAMLIBS_* are also shell variables exported to configure.ac
+dnl     shell code and Makefile.am files
+dnl   * gp_m4_* are the macros used inside those macros as m4 variables
+dnl   * gp_sh_* are the shell variables used inside the GP_ shell code
+dnl   * The old, inconsistent names of the as untouched variables
+dnl     exported to configure.ac and Makefile.am are still inconsistent.
+dnl
 dnl
-AC_DEFUN([GP_CAMLIBS_INIT],[dnl
+dnl ####################################################################
+dnl Forbid everything first, allow specific variable names later
+dnl ####################################################################
+m4_pattern_forbid([GP_CAMLIBS_])dnl
+m4_pattern_forbid([GP_CAMLIB_])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl _GP_CAMLIBS_INIT
+dnl   Called internally when required.
+dnl ####################################################################
+AC_DEFUN_ONCE([_GP_CAMLIBS_INIT],[dnl
+dnl # BEGIN $0($@)
 AC_BEFORE([$0],[GP_CAMLIB])dnl
-m4_define_default([gp_camlib_srcdir], [camlibs])dnl
-m4_define_default([gp_camlibs], [])dnl
-m4_define_default([gp_camlibs_unlisted], [])dnl
-m4_define_default([gp_camlibs_outdated], [])dnl
+AC_REQUIRE([AC_PROG_GREP])dnl
+AC_REQUIRE([AC_PROG_SED])dnl
+AC_REQUIRE([GP_PROG_CMP])dnl
+AC_REQUIRE([GP_PROG_SORT])dnl
+AC_REQUIRE([GP_PROG_TR])dnl
+AC_REQUIRE([GP_PROG_UNIQ])dnl
+m4_foreach_w([var], [everything standard unlisted outdated], [dnl
+  m4_set_empty([gp_m4s_camlib_set_]var, [], [dnl
+    m4_errprintn([Error: non-empty set gp_m4s_camlib_set_]var[ already defined])dnl
+    m4_exit(1)dnl
+  ])dnl
+])dnl
+GP_SET_DEFINE([camlib-set-standard])dnl
+GP_SET_DEFINE([camlib-set-unlisted])dnl
+GP_SET_DEFINE([camlib-set-outdated])dnl
+dnl # END $0($@)
 ])dnl
 dnl
-dnl ####################################################################
 dnl
+dnl ####################################################################
+dnl GP_CAMLIB([mycamlib])
+dnl GP_CAMLIB([mycamlib], [outdated])
+dnl   Add the camlib 'mycamlib' to the "standard" set of camlibs or
+dnl   the "outdated" set of camlibs, respectively.
+dnl ####################################################################
+m4_pattern_forbid([GP_CAMLIB])dnl
 AC_DEFUN([GP_CAMLIB],[dnl
-AC_REQUIRE([GP_CAMLIBS_INIT])dnl
+dnl # BEGIN $0($@)
+AC_REQUIRE([_GP_CAMLIBS_INIT])dnl
 AC_BEFORE([$0],[GP_CAMLIBS_DEFINE])dnl
-m4_if([$2],[unlisted],[dnl
-# $0($1,$2)
-m4_append([gp_camlibs_unlisted], [$1], [ ])dnl
-],
-[$2],[outdated],[dnl
-# $0($1,$2)
-m4_append([gp_camlibs_outdated], [$1], [ ])dnl
-],
-[$#],[1],[dnl
-# $0($1)
-m4_append([gp_camlibs], [$1], [ ])dnl
-],[dnl
-m4_errprint(__file__:__line__:[ Error:
-*** Illegal parameter 2 to $0: `$2'
-*** Valid values are: undefined, [unlisted] or [outdated]
-])dnl
+m4_case([$#],[2],[dnl
+  m4_case([$2], [unlisted], [dnl
+    GP_SET_ADD([camlib-set-unlisted], [$1])
+    m4_set_add([gp_m4s_camlib_set_unlisted], [$1])dnl
+  ], [outdated], [dnl
+    GP_SET_ADD([camlib-set-outdated], [$1])
+    m4_set_add([gp_m4s_camlib_set_outdated], [$1])dnl
+  ], [dnl
+    m4_errprintn(__file__:__line__:[ Error: Wrong second argument to GP_CAMLIB])dnl
+    m4_exit(1)dnl
+  ])dnl
+], [1], [dnl
+  GP_SET_ADD([camlib-set-standard], [$1])
+  m4_set_add([gp_m4s_camlib_set_standard], [$1])dnl
+], [dnl
+  m4_errprintn(__file__:__line__:[ Error: Wrong number of arguments to GP_CAMLIB])dnl
+  m4_exit(1)dnl
+])dnl m4_case $#
+m4_set_add([gp_m4s_camlib_set_everything], [$1], [], [dnl
+m4_errprintn(__file__:__line__:[Duplicate declaration of camlib $1])dnl
 m4_exit(1)dnl
 ])dnl
-])dnl
+dnl # END $0($@)
+])dnl AC_DEFUN GP_CAMLIB
 dnl
-dnl ####################################################################
 dnl
+dnl ####################################################################
+dnl GP_CAMLIBS_WARNING
+dnl   Print warning about building a non-"standard" set of camlibs.
+dnl ####################################################################
 AC_DEFUN([GP_CAMLIBS_WARNING],[dnl
 AC_MSG_WARN([
 
-# Caution: You have chosen to build a non-standard set of camlibs.
-#          You may have disabled the camlib required for your camera, or
-#          enabled a camlib that does *not* work, and overrides the camlib
-#          that does work. Consequently,
-#          YOUR CAMERA MAY NOT WORK!
-# 
-# Many cameras of several brands are supported by a camlib with a 
-# name different from the name of the camera brand or model. If you
-# are unsure, please
-#   * enable at least the "ptp2" camlib
-#   * or even better, just build "all" camlibs.
+  #=====================================================================#
+  # Caution: You have chosen to build a non-standard set of camlibs.    #
+  #          You may have disabled the camlib required for your camera, #
+  #          or enabled a camlib which does *not* work and overrides    #
+  #          the camlib which *does* work. Consequently,                #
+  #          YOUR CAMERA MAY NOT WORK!                                  #
+  #                                                                     #
+  # Many cameras of several brands are supported by a camlib with a     #
+  # name different from the name of the camera brand or model. If you   #
+  # are unsure, please                                                  #
+  #   * enable at least the 'ptp2' camlib                               #
+  #   * or even better, just build the standard set of camlibs.         #
+  #=====================================================================#
 ])
-sleep 2
+sleep 5
 ])
 dnl
+dnl
 dnl ####################################################################
+dnl GP_CAMLIBS_CONDITIONAL_WARNING
+dnl   Call GP_CAMLIBS_WARNING when required.
+dnl ####################################################################
+AC_DEFUN([GP_CAMLIBS_CONDITIONAL_WARNING], [dnl
+AS_VAR_IF([gp_sh_with_camlibs], [standard], [dnl
+], [dnl
+GP_CAMLIBS_WARNING
+])
+])dnl
 dnl
+dnl
+dnl ####################################################################
+dnl GP_CAMLIBS_DEFINE
+dnl   Determine the set of camlibs to build from the --with-camlibs
+dnl   parameter, and set the build variables accordingly.
+dnl ####################################################################
 AC_DEFUN([GP_CAMLIBS_DEFINE],[dnl
-AC_REQUIRE([GP_CAMLIBS_INIT])dnl
-m4_pattern_allow([m4_strip])dnl
-m4_ifval([$1],[m4_define([gp_camlib_srcdir],[$1])])dnl
-dnl for camlib in m4_strip(gp_camlibs) m4_strip(gp_camlibs_unlisted)
-dnl do
-dnl 	if test -d "$srcdir/m4_strip(gp_camlib_srcdir)/$camlib"; then :; else
-dnl 		AC_MSG_ERROR([
-dnl * Fatal:
-dnl * Source subdirectory for camlib \`$camlib' not found in
-dnl * directory \`$srcdir/m4_strip(gp_camlib_srcdir)/'
-dnl ])
-dnl 	fi
-dnl done
-AC_MSG_CHECKING([which camlibs to compile])
+# BEGIN $0($@)
+AC_REQUIRE([_GP_CAMLIBS_INIT])dnl
+AC_REQUIRE([GP_PROG_EXPR])dnl
+
+dnl GP_SET_MSG([camlib-set-standard])
+dnl GP_SET_MSG([camlib-set-outdated])
+dnl GP_SET_MSG([camlib-set-unlisted])
+
+dnl Convert sets defined at m4 time (i.e. autoreconf time)
+dnl into the same format as the sh time (i.e. configure time)
+dnl defined sets.
+m4_foreach_w([var], [everything standard outdated unlisted], [dnl
+GP_SET_DEFINE([m4-camlib-set-]var)
+GP_SET_ADD_ALL([m4-camlib-set-]var[]m4_set_listc([gp_m4s_camlib_set_]var))
+])dnl
+
+dnl GP_SET_MSG([m4-camlib-set-standard])
+dnl GP_SET_MSG([m4-camlib-set-unlisted])
+dnl GP_SET_MSG([m4-camlib-set-outdated])
+
+GP_SET_DEFINE([camlib-set-everything])dnl
+GP_SET_UNION([camlib-set-everything], [camlib-set-standard], [camlib-set-outdated], [camlib-set-unlisted])
+
+dnl GP_SET_MSG([camlib-set-everything])
+dnl GP_SET_MSG([m4-camlib-set-everything])
+
 dnl Yes, that help output won't be all that pretty, but we at least
 dnl do not have to edit it by hand.
 AC_ARG_WITH([camlibs],[AS_HELP_STRING(
 	[--with-camlibs=<list>],
 	[Compile camera drivers (camlibs) in <list>. ]dnl
-	[Drivers may be separated with commas. ]dnl
+	[Camlibs may be separated with commas. ]dnl
 	[CAUTION: DRIVER NAMES AND CAMERA NAMES MAY DIFFER. ]dnl
-	['all' is the default and compiles all camlibs, ]dnl
-	['outdated' compiles additional camlibs for very old cameras. ]dnl
-	[Possible camlibs to specify are: ]dnl
-	m4_strip(gp_camlibs)
-	[Camlibs for very old (>10 years) cameras: ]dnl
-	m4_strip(gp_camlibs_outdated))]dnl
-,
-	[camlibs="$withval"],
-	[camlibs="all"])dnl
-dnl
-ALL_DEFINED_CAMLIBS="m4_strip(gp_camlibs) m4_strip(gp_camlibs_outdated) m4_strip(gp_camlibs_unlisted)"
-ALL_DEFAULT_CAMLIBS="m4_strip(gp_camlibs)"
-BUILD_THESE_CAMLIBS_BASE=""
-INSTALL_THESE_CAMLIBS_BASE=""
-if test "$camlibs" = "all"; then
-	INSTALL_THESE_CAMLIBS_BASE="$ALL_DEFAULT_CAMLIBS"
-	AC_MSG_RESULT([all])
-else
-	# If the string starts with "all,", we start with the default list
-	# and add the explicitly defined ones later
-	if echo "$camlibs" | grep "^all," > /dev/null; then
-		INSTALL_THESE_CAMLIBS_BASE="$ALL_DEFAULT_CAMLIBS"
-		camlibs="$(echo "$camlibs" | sed 's/^all,//')"
-	fi
-	if echo "$camlibs" | grep "outdated" > /dev/null; then
-		INSTALL_THESE_CAMLIBS_BASE="$INSTALL_THESE_CAMLIBS_BASE m4_strip(gp_camlibs_outdated)"
-		camlibs="$(echo "$camlibs" | sed 's/outdated[,]*//')"
-	fi
-
-	# camlibs=$(echo $camlibs | sed 's/,/ /g')
-	IFS_save="$IFS"
-	IFS=",$IFS"
-	# Walk through enumeration of camlibs given by user and add them to list
-	# of camlibs to build if we know them.
-	for camlib in ${camlibs}; do
-		IFS="$IFS_save"
-		found=false
-		for from_all_camlib in ${ALL_DEFINED_CAMLIBS}; do
-			if test "$camlib" = "$from_all_camlib"; then
-				if test "x$INSTALL_THESE_CAMLIBS_BASE" = "x"; then
-					INSTALL_THESE_CAMLIBS_BASE="$camlib"
-				else
-					INSTALL_THESE_CAMLIBS_BASE="$INSTALL_THESE_CAMLIBS_BASE $camlib"
-				fi
-				found=:
-				break
-			fi
-		done
-		if $found; then :; else
-			AC_MSG_ERROR([Unknown camlib $camlib!])		
-		fi
-	done
-        if test "x$INSTALL_THESE_CAMLIBS_BASE" = "xcanon" ; then
-		# Gentoo mode... if user just said "canon", add "ptp2" ... should save support requests.
-		INSTALL_THESE_CAMLIBS_BASE="$INSTALL_THESE_CAMLIBS_BASE ptp2"
-		camlibs="$camlibs ptp2"
-		AC_MSG_WARN([
-		"You have just selected the old canon driver. However most current Canons\n"
-		"are supported by the PTP2 driver.\n"
-		"Autoselecting ptp2 driver too to avoid support requests.\n"
-		])
-        fi
-	IFS="$IFS_save"
-	AC_MSG_RESULT([$camlibs])
-	GP_CAMLIBS_WARNING
-	AC_DEFINE_UNQUOTED([INCOMPLETE_CAMLIB_SET], ["$INSTALL_THESE_CAMLIBS_BASE"], 
-                           [Whether the set of camlibs built is incomplete])
-fi
-BUILD_THESE_CAMLIBS=""
-for f in $ALL_DEFINED_CAMLIBS
+	['standard' is the default is a standard set of camlibs: ]dnl
+	m4_set_contents(gp_m4s_camlib_set_standard, [ ]).
+	['outdated' is a set of camlibs for very old cameras: ]dnl
+	m4_set_contents(gp_m4s_camlib_set_outdated, [ ]).dnl
+	[You can add or remove camlibs or named camlib sets by adding ]dnl
+	[them to the list with a + or - sign in front.])],
+	[gp_sh_with_camlibs="${withval}"],
+	[gp_sh_with_camlibs="standard"])dnl
+
+dnl For backwards compatibility, accept --with-camlibs='all' and
+dnl interpret it as --with-camlibs='standard'.
+AS_VAR_IF([gp_sh_with_camlibs], [all], [dnl
+  gp_sh_with_camlibs="standard"
+])dnl
+
+dnl Gentoo mode... if user just requested "canon",
+dnl add "ptp2" to save support requests.
+AS_VAR_IF([gp_sh_with_camlibs], [canon], [dnl
+	gp_sh_with_camlibs="${gp_sh_with_camlibs} ptp2"
+	AC_MSG_WARN([
+
+    #==============================================================#
+    # You have selected only the old 'canon' driver. However, most #
+    # current Canon camera models require the 'ptp2' driver.       #
+    #                                                              #
+    # Autoselecting the 'ptp2' driver in addition to the 'canon'   #
+    # driver to prevent unnecessary support requests.              #
+    #==============================================================#
+  sleep 5
+])])dnl
+
+dnl set -x
+
+AC_MSG_CHECKING([with-camlibs requested])
+AS_VAR_IF([gp_sh_with_camlibs], [standard], [dnl
+	AC_MSG_RESULT([standard set])
+], [dnl
+	gp_sh_with_camlibs="$(echo "${gp_sh_with_camlibs}" | ${TR} ',' ' ')"
+	AC_MSG_RESULT([${gp_sh_with_camlibs}])
+])
+
+dnl AC_MSG_CHECKING([for nothing])
+dnl AC_MSG_RESULT([nihil])
+
+dnl Iterate over the list of given camlibs.
+dnl
+dnl Replace 'standard', 'outdated', 'unlisted', and 'everything' with
+dnl the respective set of camlibs, and make sure any camlibs specified
+dnl explicitly are actually valid defined camlibs.
+GP_SET_DEFINE([m4-camlib-set])
+GP_SET_DEFINE([camlib-set])
+for gp_camlib in ${gp_sh_with_camlibs}
 do
-    BUILD_THESE_CAMLIBS="${BUILD_THESE_CAMLIBS}${BUILD_THESE_CAMLIBS+ }${f}.la"
+    operator="add"
+    case "X$gp_camlib" in #(
+    X-*)
+	operator=remove
+	gp_camlib="$(echo "Y${gp_camlib}" | ${SED} 's/^Y.//')"
+	;; #(
+    X+*)
+	gp_camlib="$(echo "Y${gp_camlib}" | ${SED} 's/^Y.//')"
+	;;
+    esac
+    dnl AC_MSG_CHECKING([with-camlibs operator])
+    dnl AC_MSG_RESULT([${operator}])
+    dnl AC_MSG_CHECKING([with-camlibs camlib])
+    dnl AC_MSG_RESULT([${gp_camlib}])
+
+    dnl Convert deprecated "all" parameter to "standard".
+    case "$gp_camlib" in #(
+    all)
+	AC_MSG_WARN([
+
+    #==================================================================#
+    # You have called the configure script with the --with-camlibs=all #
+    # parameter.  The name 'all' is a deprecated name for the          #
+    # 'standard' camlib set.                                           #
+    #                                                                  #
+    # Please change your call to the configure script to use           #
+    # --with-camlibs=standard instead.                                 #
+    #==================================================================#
+])
+	sleep 5
+	gp_camlib="standard"
+	;;
+    esac
+
+    dnl Now gp_camlib contains the camlib string, and operator 'add' or 'remove'.
+    case "$operator" in #(
+    add)
+        case "$gp_camlib" in #(
+        standard)
+            GP_SET_UNION([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-standard])
+            GP_SET_UNION([camlib-set], [camlib-set], [camlib-set-standard])
+            ;; #(
+        outdated)
+            GP_SET_UNION([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-outdated])
+            GP_SET_UNION([camlib-set], [camlib-set], [camlib-set-outdated])
+            ;; #(
+        unlisted)
+            GP_SET_UNION([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-unlisted])
+            GP_SET_UNION([camlib-set], [camlib-set], [camlib-set-unlisted])
+            ;; #(
+        everything)
+            GP_SET_UNION([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-everything])
+            GP_SET_UNION([camlib-set], [camlib-set], [camlib-set-everything])
+            ;; #(
+        *)
+	    GP_SET_CONTAINS_IFELSE([m4-camlib-set-everything], ["${gp_camlib}"], [dnl
+                GP_SET_ADD([m4-camlib-set], ["$gp_camlib"])
+                GP_SET_ADD([camlib-set], ["$gp_camlib"])
+            ], [dnl
+                AC_MSG_ERROR([Unknown camlib found in --with-camlibs: '${gp_camlib}'])
+            ])
+            ;;
+        esac
+	;; #(
+    remove)
+        case "$gp_camlib" in #(
+        standard)
+            GP_SET_DIFFERENCE([camlib-set], [camlib-set], [camlib-set-standard])
+            GP_SET_DIFFERENCE([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-standard])
+            ;; #(
+        outdated)
+            GP_SET_DIFFERENCE([camlib-set], [camlib-set], [camlib-set-outdated])
+            GP_SET_DIFFERENCE([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-outdated])
+            ;; #(
+        unlisted)
+            GP_SET_DIFFERENCE([camlib-set], [camlib-set], [camlib-set-unlisted])
+            GP_SET_DIFFERENCE([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-unlisted])
+            ;; #(
+        everything)
+            GP_SET_DIFFERENCE([camlib-set], [camlib-set], [camlib-set-everything])
+            GP_SET_DIFFERENCE([m4-camlib-set], [m4-camlib-set], [m4-camlib-set-everything])
+            ;; #(
+        *)
+	    GP_SET_CONTAINS_IFELSE([m4-camlib-set-everything], ["${gp_camlib}"], [dnl
+                GP_SET_REMOVE([camlib-set], ["$gp_camlib"])
+	        GP_SET_CONTAINS_IFELSE([m4-camlib-set], ["$gp_camlib"], [dnl
+                    GP_SET_REMOVE([m4-camlib-set], ["$gp_camlib"])
+		], [dnl
+		    AC_MSG_WARN([Removing camlib ${gp_camlib} from m4-camlib-set which does not contain ${gp_camlib}])
+		])
+            ], [dnl
+                AC_MSG_ERROR([Unknown camlib found in --with-camlibs: '${gp_camlib}'])
+            ])
+            ;;
+        esac
+	;;
+    esac
 done
+AS_UNSET([gp_camlib])
+AC_MSG_CHECKING([with-camlibs parsing])
+AC_MSG_RESULT([finished])
+
+dnl GP_SET_MSG([m4-camlib-set])
+dnl GP_SET_MSG([camlib-set])
+
+dnl Camlibs requested, but cannot be built.
+GP_SET_DEFINE([camlib-set-diff-skipping])
+GP_SET_DIFFERENCE([camlib-set-diff-skipping], [m4-camlib-set], [camlib-set])
+GP_SET_MSG([camlib-set-diff-skipping])
 
-INSTALL_THESE_CAMLIBS=""
-for f in $INSTALL_THESE_CAMLIBS_BASE
+dnl Camlibs added over the standard set
+GP_SET_DEFINE([camlib-set-diff-over-standard])
+GP_SET_DIFFERENCE([camlib-set-diff-over-standard], [camlib-set], [camlib-set-standard])
+GP_SET_MSG([camlib-set-diff-over-standard])
+
+dnl Camlibs missing from the standard set
+GP_SET_DEFINE([camlib-set-diff-from-standard])
+GP_SET_DIFFERENCE([camlib-set-diff-from-standard], [camlib-set-standard], [camlib-set])
+GP_SET_MSG([camlib-set-diff-from-standard])
+
+GP_SET_DEBUG_MSG([camlib-set-diff-skipping])
+GP_SET_DEBUG_MSG([camlib-set-diff-from-standard])
+GP_SET_DEBUG_MSG([camlib-set-diff-over-standard])
+
+GP_SET_SPACE_VAR([camlib-set-diff-skipping], [gp_camlib_set_skipping])dnl
+
+dnl We could use the cardinality of the difference sets to determine
+dnl how far we are from the standard set.  If we do not differ too
+dnl much, we can still show the camlib set as "standard plus these
+dnl minus those skipping that" instead of just listing the camlib
+dnl names.
+
+dnl gp_camlibs_from_standard="$(GP_SET_CARDINALITY([camlib-set-diff-from-standard]))"
+dnl AC_MSG_CHECKING([camlibs removed from standard set])
+dnl AC_MSG_RESULT([${gp_camlibs_from_standard}])
+
+dnl gp_camlibs_over_standard="$(GP_SET_CARDINALITY([camlib-set-diff-over-standard]))"
+dnl AC_MSG_CHECKING([camlibs added over standard set])
+dnl AC_MSG_RESULT([${gp_camlibs_over_standard}])
+
+dnl gp_camlibs_non_standard="$(${EXPR} ${gp_camlibs_from_standard} + ${gp_camlibs_over_standard})"
+dnl AC_MSG_CHECKING([total number of camlibs differing from standard set])
+dnl AC_MSG_RESULT([${gp_camlibs_non_standard}])
+
+AC_MSG_CHECKING([whether skipping some requested camlibs])
+AS_IF([test "x$gp_camlib_set_skipping" = "x"], [dnl
+    AC_MSG_RESULT([no])
+], [dnl
+    AC_MSG_RESULT([yes (${gp_camlib_set_skipping})])
+    AC_DEFINE_UNQUOTED([GP_CAMLIB_SET_SKIPPING], ["${gp_camlib_set_skipping}"],
+                       [If defined, the camlibs which are skipped due to missing dependencies])
+    AC_MSG_WARN([
+
+    #============================================================#
+    # We are skipping building a few requested camlibs, probably #
+    # due to missing dependencies.  Check the dependencies if    #
+    # you insist on building these camlibs.                      #
+    #============================================================#
+])
+    sleep 5
+])
+
+GP_SET_SPACE_VAR([camlib-set], [gp_camlib_set])
+AC_MSG_CHECKING([camlib set to build in detail])
+AC_MSG_RESULT([${gp_camlib_set}])
+
+GP_CAMLIBS_CONDITIONAL_WARNING
+
+dnl Whether user has requested a non-standard set of camlibs
+GP_SET_EQUAL_IFELSE([camlib-set], [camlib-set-standard], [dnl
+    AS_IF([test "x$gp_camlib_set_skipping" = "x"], [dnl
+        GP_CONFIG_MSG([Camlibs],[standard set (${gp_camlib_set})])
+    ], [dnl
+        GP_CONFIG_MSG([Camlibs],[standard set (${gp_camlib_set} SKIPPING ${gp_camlib_set_skipping})])
+    ])
+], [dnl
+    AS_IF([test "x$gp_camlib_set_skipping" = "x"], [dnl
+        GP_CONFIG_MSG([Camlibs],[non-standard set (${gp_camlib_set})])
+    ], [dnl
+        GP_CONFIG_MSG([Camlibs],[non-standard set (${gp_camlib_set} SKIPPING ${gp_camlib_set_skipping})])
+    ])
+    m4_pattern_allow([GP_CAMLIB_SET_IS_NONSTANDARD])dnl
+    AC_DEFINE_UNQUOTED([GP_CAMLIB_SET_IS_NONSTANDARD], [1],
+                       [define when the camlib set to buidl is non-standard])
+])dnl
+
+m4_pattern_allow([GP_CAMLIB_SET])dnl
+AC_DEFINE_UNQUOTED([GP_CAMLIB_SET], ["${gp_camlib_set}"],
+                   [The actually defined set of camlibs to build])
+
+AS_UNSET([GP_CAMLIB_SET])
+for f in ${gp_camlib_set}
 do
-    INSTALL_THESE_CAMLIBS="${INSTALL_THESE_CAMLIBS}${INSTALL_THESE_CAMLIBS+ }${f}.la"
+    GP_CAMLIB_SET="${GP_CAMLIB_SET}${GP_CAMLIB_SET+ }${f}.la"
 done
-AC_SUBST([BUILD_THESE_CAMLIBS])
-AC_SUBST([INSTALL_THESE_CAMLIBS])
-AC_SUBST([ALL_DEFINED_CAMLIBS])
-AC_SUBST([ALL_DEFAULT_CAMLIBS])
+AS_UNSET([f])
+AC_SUBST([GP_CAMLIB_SET])
+
+m4_pattern_allow([GP_CAMLIB_SET_EVERYTHING])dnl
+AC_SUBST([GP_CAMLIB_SET_EVERYTHING],
+         ["m4_set_contents([gp_m4s_camlib_set_everything], [ ])"])
+
+# END $0($@)
 ])dnl
 dnl
+dnl
 dnl ####################################################################
 dnl
 dnl Local Variables:
diff --git a/gphoto-m4/gp-progs.m4 b/gphoto-m4/gp-progs.m4
new file mode 100644
index 000000000..2a0df6f3a
--- /dev/null
+++ b/gphoto-m4/gp-progs.m4
@@ -0,0 +1,96 @@
+dnl ####################################################################
+dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl ####################################################################
+m4_pattern_forbid([GP_PROG_CMP])dnl
+AC_DEFUN_ONCE([GP_PROG_CMP],[dnl
+AC_ARG_VAR([CMP], [cmp file comparison command])dnl
+AC_PATH_PROG([CMP], [cmp])dnl
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl ####################################################################
+m4_pattern_forbid([GP_PROG_COMM])dnl
+AC_DEFUN_ONCE([GP_PROG_COMM],[dnl
+AC_ARG_VAR([COMM], [comm line by line comparison command])dnl
+AC_PATH_PROG([COMM], [comm])dnl
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl ####################################################################
+m4_pattern_forbid([GP_PROG_DIFF])dnl
+AC_DEFUN_ONCE([GP_PROG_DIFF],[dnl
+AC_ARG_VAR([DIFF], [diff file comparison command])dnl
+AC_PATH_PROG([DIFF], [diff])dnl
+dnl
+dnl DIFF_MAYBE_U only contains -u for readability, so if diff does not
+dnl support -u, we can still just run DIFF without -u.
+AC_MSG_CHECKING([whether DIFF supports -u])
+:>gp-empty-file-a
+:>gp-empty-file-b
+AS_IF([diff -u gp-empty-file-a gp-empty-file-b], [dnl
+       AC_MSG_RESULT([yes])
+       DIFF_MAYBE_U="${DIFF} -u"
+], [dnl
+       AC_MSG_RESULT([no])
+       DIFF_MAYBE_U="${DIFF}"
+])
+rm -f gp-empty-file-a gp-empty-file-b
+AC_SUBST([DIFF_MAYBE_U])
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl ####################################################################
+m4_pattern_forbid([GP_PROG_EXPR])dnl
+AC_DEFUN_ONCE([GP_PROG_EXPR],[dnl
+AC_ARG_VAR([EXPR], [expr expression evaluation command])dnl
+AC_PATH_PROG([EXPR], [expr])dnl
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl ####################################################################
+m4_pattern_forbid([GP_PROG_SORT])dnl
+AC_DEFUN_ONCE([GP_PROG_SORT],[dnl
+AC_ARG_VAR([SORT], [sort text file line sorting command])dnl
+AC_PATH_PROG([SORT], [sort])dnl
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl ####################################################################
+m4_pattern_forbid([^GP_PROG_TR\(])dnl
+m4_pattern_forbid([^GP_PROG_TR$])dnl
+AC_DEFUN_ONCE([GP_PROG_TR],[dnl
+AC_ARG_VAR([TR], [tr string character translation command])dnl
+AC_PATH_PROG([TR], [tr])dnl
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl ####################################################################
+m4_pattern_forbid([^GP_PROG_UNIQ\(])dnl
+m4_pattern_forbid([^GP_PROG_UNIQ$])dnl
+AC_DEFUN_ONCE([GP_PROG_UNIQ],[dnl
+AC_ARG_VAR([UNIQ], [uniq sorted file uniquification command])dnl
+AC_PATH_PROG([UNIQ], [uniq])dnl
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl Local Variables:
+dnl mode: autoconf
+dnl End:
diff --git a/gphoto-m4/gp-set.m4 b/gphoto-m4/gp-set.m4
new file mode 100644
index 000000000..0168a263d
--- /dev/null
+++ b/gphoto-m4/gp-set.m4
@@ -0,0 +1,725 @@
+dnl ######################################################################
+dnl Set operations using shell
+dnl ######################################################################
+dnl
+dnl This implements a set of set operations ('set' in the sense of
+dnl 'set theory') as shell code for use at configure time.  At m4 time
+dnl (aka autoreconf time), there already exists a set of m4_set_*
+dnl macros, but we cannot use those for user specified and
+dnl autodetected changes at configure time.
+dnl
+dnl Not all set operations are implemented, but a few basic ones we
+dnl need for gp-camlibs.m4 are.
+dnl
+dnl   * Basic definitions:
+dnl
+dnl       * GP_SET_DEFINE
+dnl       * GP_SET_UNDEFINE
+dnl
+dnl   * Operations on sets:
+dnl
+dnl       * GP_SET_ADD
+dnl       * GP_SET_ADD_ALL
+dnl       * GP_SET_REMOVE
+dnl
+dnl       * GP_SET_CARDINALITY
+dnl       * GP_SET_DIFFERENCE
+dnl       * GP_SET_UNION
+dnl
+dnl       * GP_SET_FOREACH
+dnl
+dnl   * Conditionals:
+dnl
+dnl       * GP_SET_CONTAINS_IFELSE
+dnl       * GP_SET_EMPTY_IFELSE
+dnl       * GP_SET_EQUAL_IFELSE
+dnl
+dnl       * GP_SET_CLEAN_FILES
+dnl
+dnl   * Internals and debugging help:
+dnl
+dnl       * GP_SET_CANONICALIZE
+dnl       * GP_SET_DUMP_ALL
+dnl       * GP_SET_TESTSUITE
+dnl
+dnl   * Fill shell variables with set contents:
+dnl
+dnl       * GP_SET_DEBUG_VAR
+dnl       * GP_SET_SPACE_VAR
+dnl
+dnl   * Output AC_MSG_* for GP_SET_* sets:
+dnl
+dnl       * GP_SET_DEBUG_MSG
+dnl       * GP_SET_MSG_DEBUG_RESULT
+dnl
+dnl       * GP_SET_SPACE_MSG
+dnl       * GP_SET_MSG_SPACE_RESULT
+dnl
+dnl ######################################################################
+dnl Remarks on usage and implementation of GP_SET_*
+dnl
+dnl   * Sets are stored in text files, one element per line. An empty
+dnl     file is an empty set, and empty lines mean empty elements.
+dnl     Non-empty files not ending with a newline are undefined behaviour.
+dnl
+dnl   * At this time, GP_SET_* functions work with set elements
+dnl     consisting of a limited set of characters, but the storage
+dnl     format allows for a future code cleanup to allow for handling
+dnl     more arbitrarily called elements.
+dnl
+dnl   * Set names given to GP_SET_ macros must be defined at m4
+dnl     (autoreconf) time, not at sh (configure) time.
+dnl
+dnl   * Every set must be declared before use with GP_SET_DEFINE so we
+dnl     can create an empty file for them and keep track of the name of
+dnl     that file for cleaning up later.
+dnl
+dnl   * Use GP_SET_CLEAN_FILES after your last set operations to remove
+dnl     all left over set files.
+dnl
+dnl   * Set text files may contain set elements in any order, and in
+dnl     any number. There is no difference between a set text file
+dnl     containing the same line seven times and one which only contains
+dnl     it one time.
+dnl
+dnl   * Some set operations work better or require on sorted files, so
+dnl     sometimes the implementation sorts the set text files. If you
+dnl     need a set text file sorted for some another reason, use
+dnl     GP_SET_CANONICALIZE([set-name]).
+dnl
+dnl
+dnl ######################################################################
+dnl
+dnl FIXME: Do we need to test ${COMM} works before using it?
+dnl FIXME: Do we need a sh-based replacement for ${COMM} if it is not present?
+dnl FIXME: Abort if _DIFFERENCE is called with ${COMM} not found/not working.
+dnl FIXME: Do we need to stop using shell functions?
+dnl
+dnl
+dnl ######################################################################
+dnl Try catching unexpanded macros in the output.
+dnl ######################################################################
+m4_pattern_forbid([GP_SET_])dnl
+m4_pattern_forbid([_GP_SET_])dnl
+m4_pattern_allow([GP_SET_EOF])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_INIT
+dnl   Called internally before any set operation.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_INIT], [dnl
+AC_REQUIRE([AC_PROG_GREP])dnl
+AC_REQUIRE([GP_PROG_COMM])dnl
+AC_REQUIRE([GP_PROG_SORT])dnl
+AC_REQUIRE([GP_PROG_UNIQ])dnl
+m4_set_empty([gp_set_all_sets], [], [dnl
+  m4_set_foreach([gp_set_all_sets], [elt], [dnl
+    m4_errprintn(__file__: __line__:[ Set gp_set_all_sets contains element ]elt)dnl
+  ])dnl
+  m4_errprintn(__file__:__line__:[ Error: gp_set_all_sets already defined])dnl
+  dnl m4_exit(1)dnl
+])dnl
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_FILENAME([set_name])
+dnl _GP_SET_FILENAME([set_name], [extra-extension])
+dnl   Convert set name to set file name. If present, add the given
+dnl   extra-extension to the file name in some position.
+dnl ######################################################################
+AC_DEFUN([_GP_SET_FILENAME], [dnl
+[gp-set-file--][$1]m4_if([$2],[],[],[.$2])])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_CHECK_INIT
+dnl   Implement the gp_set_shfn_check() shell function which checks that the
+dnl   given set exists and is in general working order.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_CHECK_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+gp_set_shfn_check ()
+{
+  if test -f "[$]1"; then :; else
+    AC_MSG_ERROR(["Error: set [$]1 has not been defined yet"])
+  fi
+} # gp_set_shfn_check
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_CHECK([set_name])
+dnl   Check that the given set exists and is in general working order.
+dnl   Works by calling the gp_set_shfn_check() shell function.
+dnl ######################################################################
+AC_DEFUN([_GP_SET_CHECK], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_CHECK_INIT])dnl
+gp_set_shfn_check "_GP_SET_FILENAME([$1])"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_DUMP_ALL
+dnl   Dump all sets to stdout. Intended for helping with debugging.
+dnl ######################################################################
+AC_DEFUN([GP_SET_DUMP_ALL], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+for setfile in gp-set-file--*
+do
+  AS_ECHO(["Set file: ${setfile}"])
+  ${SED} 's/^/  * <</; s/$/>>/' "${setfile}"
+done
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_DEFINE([set_name])
+dnl   Declare a set of given name, initializing it to an empty set.
+dnl   Not a shell function, as the emitted shell code is shorter than
+dnl   calling a shell function.
+dnl ######################################################################
+AC_DEFUN([GP_SET_DEFINE], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+m4_set_add([gp_set_all_sets], [$1])dnl
+: > "_GP_SET_FILENAME([$1])"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_UNDEFINE([set_name])
+dnl   Undefine a set of given name, removing its file.
+dnl   Not a shell function, as the emitted shell code is shorter than
+dnl   calling a shell function.
+dnl ######################################################################
+AC_DEFUN([GP_SET_UNDEFINE], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+_GP_SET_CHECK([$1])dnl
+rm -f "_GP_SET_FILENAME([$1])"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_ADD_INIT
+dnl   Implement the gp_set_shfn_set_add() shell function which adds a given
+dnl   element to a given set.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_ADD_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_CHECK_INIT])dnl
+gp_set_shfn_set_add ()
+{
+  gp_set_shfn_check "[$]1"
+  AS_ECHO(["[$]2"]) >> "[$]1"
+} # gp_set_shfn_set_add
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_ADD([set_name], [element])
+dnl   Add the given element to the given set. Implemented by calling the
+dnl   gp_set_shfn_set_add() shell function.
+dnl   Note: Unlike m4_set_add, this does not handle IF-UNIQ and IF-DUP
+dnl   macro parameters.
+dnl ######################################################################
+AC_DEFUN([GP_SET_ADD], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_ADD_INIT])dnl
+gp_set_shfn_set_add "_GP_SET_FILENAME([$1])" "$2"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_ADD_ALL([set_name], [element]...)
+dnl   Add the given elements to the given set, similar to m4_set_add_all.
+dnl   This can be very useful for initializing a GP_SET_* set from a
+dnl   m4_set_* in one go.
+dnl   Not a shell function, as the emitted shell code is shorter than
+dnl   calling a shell function.
+dnl ######################################################################
+AC_DEFUN([GP_SET_ADD_ALL], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+_GP_SET_CHECK([$1])dnl
+cat>>"_GP_SET_FILENAME([$1])"<<_GP_EOF
+m4_foreach([myvar], [m4_shift($@)], [dnl
+myvar
+])dnl
+_GP_EOF
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_REMOVE_INIT
+dnl   Implement the gp_set_shfn_remove() shell function removing a given
+dnl   element from a given set.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_REMOVE_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+gp_set_shfn_remove ()
+{
+  gp_set_shfn_check "[$]1"
+  ${GREP} -v "^[$]2$" < "[$]1" > "[$]1.tmp"
+  mv -f "[$]1.tmp" "[$]1"
+} # gp_set_shfn_remove
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_REMOVE([set_name], [element])
+dnl   Remove a given element from a given set.
+dnl   Calls the gp_set_shfn_remove() shell function for the actual work.
+dnl ######################################################################
+AC_DEFUN([GP_SET_REMOVE], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_REMOVE_INIT])dnl
+gp_set_shfn_remove "_GP_SET_FILENAME([$1])" "$2"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_UNION_INIT
+dnl   Define the gp_set_shfn_union() shell function which defines a
+dnl   result set as the union of 0 or more sets.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_UNION_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+dnl This functions uses the shell builtin 'shift', so it needs to store
+dnl the original $1 in a local variable.
+gp_set_shfn_union ()
+{
+  local result_fname="[$]1"
+  gp_set_shfn_check "[$]result_fname"
+  if shift; then
+    cat "[$]@" > "[$]{result_fname}.tmp"
+    mv -f "[$]{result_fname}.tmp" "[$]{result_fname}"
+  fi
+} # gp_set_shfn_union
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_UNION([result_set], [setname]...)
+dnl   Define result_set as the union of 0 or more setnames.
+dnl   Calls the gp_set_shfn_union() shell function for the actual work.
+dnl ######################################################################
+AC_DEFUN([GP_SET_UNION], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_UNION_INIT])dnl
+m4_set_add([gp_set_all_sets], [$1])dnl
+gp_set_shfn_union m4_foreach([setname], [$@], [ "_GP_SET_FILENAME(setname)"])
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_DIFFERENCE_INIT([result_set_fname], [set_fname]...)
+dnl   This uses comm(1), which is a POSIX command. We can always
+dnl   re-implement comm(1) with a lot of speed penalties in a bunch
+dnl   of nested sh loops if we run into a system which does not have
+dnl   comm(1) installed.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_DIFFERENCE_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_CHECK_INIT])dnl
+AC_REQUIRE([_GP_SET_CANONICALIZE_INIT])dnl
+dnl This functions uses the shell builtin 'shift', so it needs to store
+dnl the original $1 and $2 in local variables.
+gp_set_shfn_difference ()
+{
+  local result_fname="[$]1"
+  gp_set_shfn_check "[$]result_fname"
+  if shift; then
+    gp_set_shfn_canonicalize "[$]1"
+    cat "[$]1" > "[$]result_fname"
+    if shift; then
+      for gp_s
+      do
+        gp_set_shfn_canonicalize "[$]gp_s"
+        ${COMM} -23 "[$]{result_fname}" "[$]gp_s" > "[$]{result_fname}.tmp"
+        mv -f "[$]{result_fname}.tmp" "[$]{result_fname}"
+      done
+    fi
+  fi
+} # gp_set_shfn_difference
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_DIFFERENCE([result_set], [setname]...)
+dnl   Define result_set as the first setname with the element of all
+dnl   the other sets removed from it.
+dnl ######################################################################
+AC_DEFUN([GP_SET_DIFFERENCE], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_DIFFERENCE_INIT])dnl
+m4_set_add([gp_set_all_sets], [$1])dnl
+gp_set_shfn_difference m4_foreach([setname], [$@], [ "_GP_SET_FILENAME(setname)"])
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_CARDINALITY_INIT
+dnl   Define gp_set_shfn_cardinality() shell function which writes
+dnl   set cardinality to stdout.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_CARDINALITY_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+gp_set_shfn_cardinality ()
+{
+  gp_set_shfn_check "[$]1"
+  wc -l < "[$]1"
+} # gp_set_shfn_cardinality
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_CARDINALITY([set_name])
+dnl   Write set cardinality to stdout.
+dnl ######################################################################
+AC_DEFUN([GP_SET_CARDINALITY], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_CARDINALITY_INIT])dnl
+gp_set_shfn_cardinality "_GP_SET_FILENAME([$1])"])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_EMPTY_IFELSE([set_name], [if-empty], [if-not-empty])
+dnl   Run if-empty block or if-not-empty block, depending on whether
+dnl   the named set is empty or not.
+dnl ######################################################################
+AC_DEFUN([GP_SET_EMPTY_IFELSE], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+_GP_SET_CHECK([$1])dnl
+AS_IF([test "0" -eq "$(wc -l < "_GP_SET_FILENAME([$1])")"], m4_shift($@))
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_EQUAL_IFELSE([set_a], [set_b], [if-equal], [if-not-equal])
+dnl   When set_a and set_b are equal, run the if-equal block. Otherwise,
+dnl   run the if-not-equal block.
+dnl ######################################################################
+AC_DEFUN([GP_SET_EQUAL_IFELSE], [dnl
+gp_set_shfn_canonicalize "_GP_SET_FILENAME([$1])"
+gp_set_shfn_canonicalize "_GP_SET_FILENAME([$2])"
+AS_IF([${CMP} "_GP_SET_FILENAME([$1])" "_GP_SET_FILENAME([$2])" > /dev/null 2>&1],
+      m4_shift2($@))
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_CONTAINS_IFELSE([set_name], [element], [yes-block], [no-block])
+dnl   If set_name contains element, run the yes-block. Otherwise,
+dnl   run the no-block.
+dnl ######################################################################
+AC_DEFUN([GP_SET_CONTAINS_IFELSE], [dnl
+_GP_SET_CHECK([$1])dnl
+AS_IF([test "0" -lt "$(${GREP} -c "^$2\$" < "_GP_SET_FILENAME([$1])")"],
+      m4_shift2($@))
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_DEBUG_VAR_INIT
+dnl   Define gp_set_shfn_debug_var() shell function which sets a shell
+dnl   variable to a string representing a human readable form for of
+dnl   the given set.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_DEBUG_VAR_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+gp_set_shfn_debug_var ()
+{
+  gp_set_shfn_check "[$]1"
+  gp_set_shfn_canonicalize "[$]1"
+  local element
+  local gp_set_is_first=:
+  local gp_set_saved_ifs="$IFS"
+  IFS=""
+  while read element
+  do
+    if "$gp_set_is_first"
+    then
+      eval "[$]2=\"{ \""
+      gp_set_is_first=false
+    else
+      eval "[$]2=\"\${[$]2}, \""
+    fi
+    if test "x$element" = "x"
+    then
+      eval "[$]2=\"\${[$]2}''\""
+    else
+      eval "[$]2=\"\${[$]2}'\$element'\""
+    fi
+  done < "[$]1"
+  IFS="$gp_set_saved_ifs"
+  if "$gp_set_is_first"
+  then
+    eval "[$]2=\"{ }\""
+  else
+    eval "[$]2=\"\${[$]2} }\""
+  fi
+} # gp_set_shfn_debug_var
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_DEBUG_VAR([set_name], [shell_var_name])
+dnl   Set shell variable shell_var_name to a string representing a human
+dnl   readable for of the given set.
+dnl ######################################################################
+AC_DEFUN([GP_SET_DEBUG_VAR], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_DEBUG_VAR_INIT])dnl
+gp_set_shfn_debug_var "_GP_SET_FILENAME([$1])" "$2"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_DEBUG_MSG([set-name])
+dnl   For a given set, expand to a simple pair of AC_MSG_CHECKING and
+dnl   AC_MSG_RESULT showing the GP_SET_DEBUG_VAR, mostly to help with
+dnl   debugging.
+dnl ######################################################################
+AC_DEFUN([GP_SET_DEBUG_MSG], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_MSG_CHECKING([value of set ]$1)
+GP_SET_MSG_DEBUG_RESULT([$1])
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_SPACE_MSG([set-name])
+dnl   For a given set, expand to a simple pair of AC_MSG_CHECKING and
+dnl   AC_MSG_RESULT showing the GP_SET_SPACE_VAR, both to help with
+dnl   debugging gp-set.m4 and possibly for produnction use.
+dnl ######################################################################
+AC_DEFUN([GP_SET_MSG], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_MSG_CHECKING([value of set ]$1)
+GP_SET_MSG_RESULT([$1])
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_SPACE_VAR([set-name], [var-name])
+dnl ######################################################################
+AC_DEFUN([GP_SET_SPACE_VAR], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+$2=""
+GP_SET_FOREACH([$1], [element], [dnl
+AS_IF([test "x[$]$2" = "x"], [dnl
+  $2="[$]element"
+], [dnl
+  $2="[$]$2 [$]element"
+])
+])
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_MSG_RESULT([set-name])
+dnl   Shortcut for setting a shell variable to a space separated list of
+dnl   elements, and then expanding to AC_MSG_RESULT([$shellvar]).
+dnl ######################################################################
+AC_DEFUN([GP_SET_MSG_RESULT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+GP_SET_SPACE_VAR([$1], [gp_set_msg_result_var])dnl
+AC_MSG_RESULT([${gp_set_msg_result_var}])
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_MSG_DEBUG_RESULT([set-name])
+dnl   Shortcut for setting a shell variable to a human readable list of
+dnl   elements, and then expanding to AC_MSG_RESULT([$shellvar]).
+dnl ######################################################################
+AC_DEFUN([GP_SET_MSG_DEBUG_RESULT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+GP_SET_DEBUG_VAR([$1], [gp_set_msg_result_var])dnl
+AC_MSG_RESULT([${gp_set_msg_result_var}])
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl _GP_SET_CANONICALIZE_INIT
+dnl   Implement the gp_set_shfn_canonicalize() shell function.
+dnl ######################################################################
+AC_DEFUN_ONCE([_GP_SET_CANONICALIZE_INIT], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+gp_set_shfn_canonicalize ()
+{
+  gp_set_shfn_check "[$]1"
+  { set -e
+    [$]{SORT} < "[$]1" | [$]{UNIQ} > "[$]1.tmp"
+    mv -f "[$]1.tmp" "[$]1"; }
+} # gp_set_shfn_canonicalize
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_CANONICALIZE([set_name])
+dnl   Convert the set file for set_name into a canonical form.
+dnl
+dnl   Implementation detail: Sorts the lines, and makes them unique.
+dnl ######################################################################
+AC_DEFUN([GP_SET_CANONICALIZE], [dnl
+AC_REQUIRE([_GP_SET_INIT])dnl
+AC_REQUIRE([_GP_SET_CANONICALIZE_INIT])dnl
+gp_set_shfn_canonicalize "_GP_SET_FILENAME([$1])"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_FOREACH([set_name], [shell-var], [shell-block])
+dnl   For each element in set_name, run the shell-block with the given
+dnl   shell variable set to every element in turn.
+dnl ######################################################################
+AC_DEFUN([GP_SET_FOREACH], [dnl
+_GP_SET_CHECK([$1])dnl
+gp_set_saved_ifs="$IFS"
+IFS=""
+while read $2
+do
+  IFS="$gp_set_saved_ifs"
+  $3
+done < "_GP_SET_FILENAME([$1])"
+IFS="$gp_set_saved_ifs"
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_CLEAN_FILES
+dnl   Remove all the files used for storing sets. Invoke this macro near
+dnl   the end of configure.ac after you have finished doing anything with
+dnl   GP_SET_* sets.
+dnl ######################################################################
+AC_DEFUN([GP_SET_CLEAN_FILES], [dnl
+AC_BEFORE([_GP_SET_INIT], [$0])dnl
+AC_BEFORE([GP_SET_DEFINE], [$0])dnl
+AC_BEFORE([GP_SET_UNDEFINE], [$0])dnl
+AC_BEFORE([GP_SET_ADD], [$0])dnl
+AC_BEFORE([GP_SET_ADD_ALL], [$0])dnl
+AC_BEFORE([GP_SET_REMOVE], [$0])dnl
+AC_BEFORE([GP_SET_EMPTY_IFELSE], [$0])dnl
+AC_BEFORE([GP_SET_EQUAL_IFELSE], [$0])dnl
+AC_BEFORE([GP_SET_CONTAINS_IFELSE], [$0])dnl
+AC_BEFORE([GP_SET_DEBUG_VAR], [$0])dnl
+AC_BEFORE([GP_SET_SPACE_VAR], [$0])dnl
+dnl
+dnl GP_SET_DUMP_ALL()dnl
+dnl
+dnl m4_set_foreach([gp_set_all_sets], [set_name], [dnl
+dnl AS_ECHO(["Set defined somewhere: set_name"])
+dnl ])dnl
+dnl
+[rm -f]m4_set_foreach([gp_set_all_sets], [setname],
+                      [ "_GP_SET_FILENAME(setname)"])dnl
+])dnl
+dnl
+dnl
+dnl ######################################################################
+dnl GP_SET_TESTSUITE()
+dnl   Does a number of tests for the GP_SET_* macros.
+dnl
+dnl   Should be mostly useful while debugging gp-set.m4 itself.
+dnl ######################################################################
+AC_DEFUN([GP_SET_TESTSUITE], [dnl
+# BEGIN $0
+_GP_SET_INIT
+
+GP_SET_DEFINE([foo])
+GP_SET_DEFINE([bar])
+GP_SET_DEFINE([foobar])
+GP_SET_DEFINE([everything])
+
+GP_SET_DEBUG_MSG([foo])
+
+GP_SET_DEFINE([bax])
+GP_SET_UNDEFINE([bax])
+
+GP_SET_UNDEFINE([bar])
+GP_SET_DEFINE([bar])
+
+dnl GP_SET_ADD([moo], [meh])
+GP_SET_ADD_ALL([everything], [foo], [bar], [bar ], [bla])
+
+GP_SET_DUMP_ALL
+
+m4_set_add_all([m4testset], [a], [b c], [d e], [f], [g])
+AC_MSG_CHECKING([for value of m4 testset])
+AC_MSG_RESULT([m4_set_contents([m4testset], [, ])])
+
+GP_SET_ADD_ALL([everything]m4_set_listc([m4testset]))
+
+GP_SET_DUMP_ALL
+
+GP_SET_ADD([foo], [barfoo])
+GP_SET_ADD([foo], [foobar])
+GP_SET_ADD([foo], [fox])
+GP_SET_ADD([foo], [fux])
+GP_SET_ADD([foo], [fox])
+GP_SET_ADD([foo], [])
+GP_SET_ADD([foo], [fox])
+GP_SET_ADD([foo], [barfoo])
+GP_SET_ADD([foo], [ barfoo])
+GP_SET_ADD([foo], ["barfoo "])
+GP_SET_ADD([foo], [])
+GP_SET_REMOVE([foo], [fox])
+GP_SET_ADD([foo], [barfoo])
+
+GP_SET_ADD([foobar], [bar])
+GP_SET_ADD([foobar], [foobar])
+GP_SET_ADD([foobar], [barfoo])
+
+GP_SET_DEBUG_MSG([foo])
+
+GP_SET_MSG([bar])
+GP_SET_MSG([foo])
+GP_SET_MSG([foobar])
+GP_SET_MSG([everything])
+
+GP_SET_DEFINE([union])
+GP_SET_UNION([union], [foo], [bar], [foobar])
+AC_MSG_CHECKING([value of union of foo bar foobar])
+GP_SET_MSG_RESULT([union])
+
+GP_SET_DEFINE([difference])
+GP_SET_DIFFERENCE([difference], [foo], [bar], [foobar])
+GP_SET_MSG([difference])
+
+AC_MSG_CHECKING([whether sets foo and bar are equal])
+GP_SET_EQUAL_IFELSE([foo], [bar], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no])])
+
+AC_MSG_CHECKING([whether set foo is empty])
+GP_SET_EMPTY_IFELSE([foo], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no])])
+
+AC_MSG_CHECKING([whether set bar is empty])
+GP_SET_EMPTY_IFELSE([bar], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no])])
+
+AC_MSG_CHECKING([whether set foo contains element bar])
+GP_SET_CONTAINS_IFELSE([foo], [bar], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no])])
+
+AC_MSG_CHECKING([whether set foobar contains element bar])
+GP_SET_CONTAINS_IFELSE([foobar], [bar], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no])])
+
+GP_SET_FOREACH([foobar], [gp_set_var], [dnl
+  AC_MSG_CHECKING([foobar element])
+  AC_MSG_RESULT([${gp_set_var}])
+])dnl
+GP_SET_FOREACH([foobar], [gp_set_var], [dnl
+  AS_ECHO(["  * element ${gp_set_var}"])
+])dnl
+GP_SET_FOREACH([foobar], [gp_set_var], [echo "  * ELEMENT ${gp_set_var}"])dnl
+AS_ECHO(["Moo."])
+
+GP_SET_DUMP_ALL
+# END $0
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
+dnl Local Variables:
+dnl mode: autoconf
+dnl End:
diff --git a/libgphoto2/gphoto2-version.c b/libgphoto2/gphoto2-version.c
index bacf06a34..6cf16254c 100644
--- a/libgphoto2/gphoto2-version.c
+++ b/libgphoto2/gphoto2-version.c
@@ -34,12 +34,23 @@ const char **gp_library_version(GPVersionVerbosity verbose)
 	static const char *shrt[] =
 		{
 			PACKAGE_VERSION,
-#ifdef INCOMPLETE_CAMLIB_SET
-			"INCOMPLETE CAMLIB SET ("
-			INCOMPLETE_CAMLIB_SET
+#if GP_CAMLIB_SET_IS_NONSTANDARD
+			"NON-STANDARD CAMLIB SET"
+			" ("
+			GP_CAMLIB_SET
+#ifdef GP_CAMLIB_SET_SKIPPING
+			" SKIPPING "
+			GP_CAMLIB_SET_SKIPPING
+#endif
 			")",
 #else
-			"all camlibs",
+			"standard camlibs"
+#ifdef GP_CAMLIB_SET_SKIPPING
+			" (SKIPPING "
+			GP_CAMLIB_SET_SKIPPING
+			")"
+#endif
+			,
 #endif
 #ifdef HAVE_CC
 			HAVE_CC,
@@ -61,12 +72,30 @@ const char **gp_library_version(GPVersionVerbosity verbose)
 	static const char *verb[] =
 		{
 			PACKAGE_VERSION,
-#ifdef INCOMPLETE_CAMLIB_SET
-			"INCOMPLETE CAMLIB SET ("
-			INCOMPLETE_CAMLIB_SET
+#if GP_CAMLIB_SET_IS_NONSTANDARD
+			"NON-STANDARD CAMLIB SET"
+#ifdef GP_CAMLIB_SET_SKIPPING
+			" SKIPPING SOME"
+#endif
+			" ("
+			GP_CAMLIB_SET
+#ifdef GP_CAMLIB_SET_SKIPPING
+			" SKIPPING "
+			GP_CAMLIB_SET_SKIPPING
+#endif
 			")",
 #else
-			"all camlibs",
+			"standard camlib set"
+#ifdef GP_CAMLIB_SET_SKIPPING
+			" SKIPPING SOME"
+#endif
+			" ("
+			GP_CAMLIB_SET
+#ifdef GP_CAMLIB_SET_SKIPPING
+			" SKIPPING "
+			GP_CAMLIB_SET_SKIPPING
+#endif
+			")",
 #endif
 #ifdef HAVE_CC
 			HAVE_CC " (C compiler used)",