Make downloading tags optional.

Allow networking to be disabled - may be useful for developers with
no connection to Internet. By default networking is paired with
maintainer mode, that is - it is enabled/disabled when maintainer mode
is enabled/disabled.

* configure.ac: Check for networking. Check for wget and curl if
networking is enabled.
* Makefile.am: Use NETWORK_ENABLED condition.

2 files changed, 44 insertions, 8 deletions

diff --git a/Makefile.am b/Makefile.am
index 6e5ba02..50d11c1 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -123,13 +123,18 @@ download_wget = $(WGET) -N -nd -T 300 -t 5 -P $(dir $@)
 subst_manpage = $(SED) 's|[@]PACKAGE_STRING[@]|$(PACKAGE_STRING)|g;s|[@]docdir[@]|$(docdir)|g'
 srctar_stdout = cd $(top_srcdir) >/dev/null && $(TAR) chof -
 
-# If maintainer mode is enabled, always check the remote locations
-# of the tag files for updates when building the default target.
+# If maintainer mode is enabled and network is enabled then always
+# check the remote locations of the tag files for updates when
+# building the default target.
 if MAINTAINER_MODE
+if NETWORK_ENABLED
 check_updates = $(if $(filter all%,$(or $(MAKECMDGOALS),all)),$(dist_doctags_DATA))
 else
 check_updates =
 endif
+else
+check_updates =
+endif
 
 .PHONY: $(check_updates) postinst-acdir-notice
 
@@ -138,9 +143,15 @@ endif
 
 # Download the libstdc++ tag file from the GCC website.
 doctags/libstdc++.tag:
-	$(AM_V_GEN)$(if\
+	$(AM_V_GEN)$(if $(filter no,$(USE_NETWORK)),\
+	echo 'Error: $@ does not exist.';\
+	echo 'Downloading it is not possible because network is disabled.';\
+	echo 'Please run configure script with --enable-network flag.';\
+	echo 'Bailing out.' >&2;\
+	exit 1;,\
+	$(if\
 	$(CURL),$(download_curl) '$(libstdcxx_tag_url)',$(if\
-	$(WGET),$(download_wget) '$(libstdcxx_tag_url)',test -f $@))
+	$(WGET),$(download_wget) '$(libstdcxx_tag_url)',test -f $@)))
 
 # Build the mm-common-prepare(1) manual page.
 util/mm-common-prepare.1: $(srcdir)/util/mm-common-prepare.1.in Makefile
diff --git a/configure.ac b/configure.ac
index 10f2320..d437cc2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -32,11 +32,36 @@ AC_PROG_SED
 dnl list of tar execs is taken from the generated ./missing script.
 AC_CHECK_PROGS([TAR], [tar gnutar gtar], [no])
 AS_VAR_IF([TAR], [no], [AC_MSG_ERROR([tar utility not found])])
-AC_CHECK_PROG([CURL], [curl], [curl])
-AC_CHECK_PROG([WGET], [wget], [wget])
 
-AS_IF([test "x$USE_MAINTAINER_MODE" != xno && test "x$CURL$WGET" = x],
-      [AC_MSG_FAILURE([[Either curl or wget is required for building mm-common.]])])
+AC_MSG_CHECKING([whether to enable network])
+AC_ARG_ENABLE([network],
+              [AS_HELP_STRING([--enable-network],
+                              [use network to download tags if needed @<:@default=same as maintainer mode@:>@])],
+              [AS_VAR_IF([enableval], ['yes'],,
+                         [AS_VAR_IF([enableval], ['no'],,
+                                    [AC_MSG_ERROR([[Pass either `yes', `no' or nothing to --enable-network.]])]
+                                   )
+                         ]
+                        )
+               AS_VAR_SET([enable_network], ["$enableval"])
+              ],
+              [AS_VAR_SET([enable_network], ["$USE_MAINTAINER_MODE"])]
+             )
+AC_SUBST([USE_NETWORK], ["$enable_network"])
+AM_CONDITIONAL(NETWORK_ENABLED, [test "x$enable_network" = 'xyes'])
+AC_MSG_RESULT([$USE_NETWORK])
+
+AS_VAR_IF([USE_NETWORK], ['yes'],
+          [AC_CHECK_PROG([CURL], [curl], [curl])
+           AC_CHECK_PROG([WGET], [wget], [wget])
+           AS_VAR_IF([CURL], [],
+                     [AS_VAR_IF([WGET], [],
+                                [AC_MSG_FAILURE([[Network is enabled so either curl or wget is required for building mm-common.]])]
+                               )
+                     ]
+                    )
+          ]
+         )
 
 AC_CONFIG_FILES([Makefile
                  doctags/mm-common-libstdc++.pc