Merge branch 'branch-1.13.2' into maint

* branch-1.13.2:
  maint: targets and recipes to simplify testing on real-world packages
  build: preparatory refactoring
  build: tiny reduction in code duplication
  make flags analysis: handle more options with args
  make flags analysis: use simpler variable names
  make flags analysis: whitespace changes
  make flags analysis: embed in a subshell
  make flags analysis: be more robust
  make flags analysis: cater to GNU make 3.83 (still unreleased as of now)
  tests: expose weaknesses in make flags analysis
  tests: improve debugging output in checks on make flags analysis
  make flags analysis: refactor, to reduce code duplication
  tests: avoid one tricky use of "make -e"
  tests: avoid a spurious error with Solaris make
  subdirs: don't return false positives for the '-k' option's presence
  header-vars: recognize more make flags ('-k' in particular)
  header-vars: simplify how make flags are determined
  tests: remove dead code from t/make-dryrun.tap
  header-vars: new variable $(am__running_with_option)
  tests: expose bug#12554 (false positives for presence of '-k' make option)

2 files changed, 83 insertions, 50 deletions

diff --git a/lib/am/header-vars.am b/lib/am/header-vars.am
index d2f098425..4b9cc04cb 100644
--- a/lib/am/header-vars.am
+++ b/lib/am/header-vars.am
@@ -31,54 +31,88 @@ VPATH = @srcdir@
 ## enough for now.
 am__is_gnu_make = test -n '$(MAKEFILE_LIST)' && test -n '$(MAKELEVEL)'
 
+## Shell code that determines whether the current make instance is
+## running with a given one-letter option (e.g., -k, -n) that takes
+## no argument.  Actually, the only supported option at the moment
+## is '-n' (support for '-k' will be added soon).
+am__make_running_with_option = \
+  case $${target_option-} in \
+      ?) ;; \
+      *) echo "am__make_running_with_option: internal error: invalid" \
+              "target option '$${target_option-}' specified" >&2; \
+         exit 1;; \
+  esac; \
+  has_opt=no; \
+  sane_makeflags=$$MAKEFLAGS; \
+  if $(am__is_gnu_make); then \
+## The format of $(MAKEFLAGS) is quite tricky with GNU make; the
+## variable $(MFLAGS) behaves much better in that regard.  So use it.
+    sane_makeflags=$$MFLAGS; \
+  else \
+## Non-GNU make: we must rely on $(MAKEFLAGS).  This is tricker and more
+## brittle, but is the best we can do.
+    case $$MAKEFLAGS in \
+## If we run "make TESTS='snooze nap'", FreeBSD make will export MAKEFLAGS
+## to " TESTS=foo\ nap", so that the simpler loop below (on word-splitted
+## $$MAKEFLAGS) would see a "make flag" equal to "nap", and would wrongly
+## misinterpret that as and indication that make is running in dry mode.
+## This has already happened in practice.  So we need this hack.
+      *\\[\ \	]*) \
+## Extra indirection with ${bs} required by FreeBSD 8.x make.
+## Not sure why (so sorry for the cargo-cult programming here).
+        bs=\\; \
+        sane_makeflags=`printf '%s\n' "$$MAKEFLAGS" \
+          | sed "s/$$bs$$bs[$$bs $$bs	]*//g"`;; \
+    esac; \
+  fi; \
+  skip_next=no; \
+  strip_trailopt () \
+  { \
+    flg=`printf '%s\n' "$$flg" | sed "s/$$1.*$$//"`; \
+  }; \
+  for flg in $$sane_makeflags; do \
+    test $$skip_next = yes && { skip_next=no; continue; }; \
+    case $$flg in \
+      *=*|--*) continue;; \
+##
+## GNU make 3.83 has changed the format of $MFLAGS, and removed the space
+## between an option and its argument (e.g., from "-I dir" to "-Idir").
+## So we need to handle both formats, at least for options valid in GNU
+## make.  OTOH, BSD make formats $(MAKEFLAGS) by separating all options,
+## and separating any option from its argument, so things are easier
+## there.
+##
+## For GNU make and BSD make.
+        -*I) strip_trailopt 'I'; skip_next=yes;; \
+      -*I?*) strip_trailopt 'I';; \
+## For GNU make >= 3.83.
+        -*O) strip_trailopt 'O'; skip_next=yes;; \
+      -*O?*) strip_trailopt 'O';; \
+## For GNU make (possibly overkill, this one).
+        -*l) strip_trailopt 'l'; skip_next=yes;; \
+      -*l?*) strip_trailopt 'l';; \
+## For BSD make.
+      -[dEDm]) skip_next=yes;; \
+## For NetBSD make.
+      -[JT]) skip_next=yes;; \
+    esac; \
+    case $$flg in \
+      *$$target_option*) has_opt=yes; break;; \
+    esac; \
+  done; \
+  test $$has_opt = yes
+
 ## Shell code that determines whether make is running in "dry mode"
 ## ("make -n") or not.  Useful in rules that invoke make recursively,
 ## and are thus executed also with "make -n" -- either because they
 ## are declared as dependencies to '.MAKE' (NetBSD make), or because
 ## their recipes contain the "$(MAKE)" string (GNU and Solaris make).
-am__make_dryrun = \
-  { \
-    am__dry=no; \
-    if $(am__is_gnu_make); then \
-## GNU make: $(MAKEFLAGS) is quite tricky there, and the older
-## $(MFLAGS) variable behaves much better.
-      for am__flg in $$MFLAGS; do \
-        case $$am__flg in \
-          *=*|--*) ;; \
-          -*n*) am__dry=yes; break;; \
-        esac; \
-      done; \
-    else \
-## Non-GNU make: we must rely on $(MAKEFLAGS).  This is tricky and brittle,
-## but is the best we can do.
-      case $$MAKEFLAGS in \
-## If we run "make TESTS='snooze nap'", FreeBSD make will export MAKEFLAGS
-## to " TESTS=foo\ nap", so that the simpler loop below (on word-splitted
-## $$MAKEFLAGS) would see a "make flag" equal to "nap", and would wrongly
-## misinterpret that as and indication that make is running in dry mode.
-## This has already happened in practice.  So we need this unpleasant hack.
-         *\\[\ \	]*) \
-           echo 'am--echo: ; @echo "AM"  OK' | $(MAKE) -f - 2>/dev/null \
-             | grep '^AM OK$$' >/dev/null || am__dry=yes ;; \
-         *) \
-	   am__skip_next=no; \
-           for am__flg in $$MAKEFLAGS; do \
-	     if test $$am__skip_next = yes; then \
-	       am__skip_next=no; \
-	       continue; \
-	     fi; \
-             case $$am__flg in \
-               *=*|--*) ;; \
-## Quite ugly special-casing.  We might need other similar, but let's
-## wait until the need arises.
-	       -I) am__skip_next=yes;; \
-               *n*) am__dry=yes; break;; \
-             esac; \
-           done ;;\
-       esac; \
-    fi; \
-    test $$am__dry = yes; \
-  }
+am__make_dryrun = (target_option=n; $(am__make_running_with_option))
+
+## Shell code that determines whether make is running in "keep-going mode"
+## ("make -k") or not.  Useful in rules that must recursively descend into
+## subdirectories, and decide whther to stop at the first error or not.
+am__make_keepgoing = (target_option=k; $(am__make_running_with_option))
 
 ## Some derived variables that have been found to be useful.
 pkgdatadir = $(datadir)/@PACKAGE@
diff --git a/lib/am/subdirs.am b/lib/am/subdirs.am
index c4c3694cb..999aa7877 100644
--- a/lib/am/subdirs.am
+++ b/lib/am/subdirs.am
@@ -39,13 +39,12 @@ AM_RECURSIVE_TARGETS += $(am__recursive_targets:-recursive=)
 $(am__recursive_targets):
 ## Using $failcom allows "-k" to keep its natural meaning when running a
 ## recursive rule.
-	@fail= failcom='exit 1'; \
-	for f in x $$MAKEFLAGS; do \
-	  case $$f in \
-	    *=* | --[!k]*);; \
-	    *k*) failcom='fail=yes';; \
-	  esac; \
-	done; \
+	@fail=; \
+	if $(am__make_keepgoing); then \
+	  failcom='fail=yes'; \
+	else \
+	  failcom='exit 1'; \
+	fi; \
 	dot_seen=no; \
 	target=`echo $@ | sed s/-recursive//`; \
 ## For distclean and maintainer-clean we make sure to use the full