Merge remote-tracking branch 'origin/maint'

* origin/maint:
  maint: update gnu-web-doc-update.
  maint: post-release administrivia
  version 2.6
  maint: prepare for release 2.6
  maint: post-release administrivia
  version 2.5.91
  maint: prepare NEWS.
  maint: fix spaces.
  tests: adjust to case where the C compiler is actually a C++ compiler
  tests: fix dependencies
  doc: fix Texinfo command
  maint: Valgrind on OS X.
  tests: be sure that backups are safe.
  maint: dead comment.
  tests: refactor for legibility.
  tests: refactor the bison invocations.
  maint: fix syntax-check ignore patterns.
  gnulib: update
  gnulib: update.
  gnulib: update

Conflicts:
	build-aux/Makefile.am
	cfg.mk
	tests/Makefile.am

Makefile.am

@@ -96,6 +96,7 @@ gen-ChangeLog:
 	    --strip-cherry-pick				\
 	    --no-cluster				\
 	    --amend=$(srcdir)/build-aux/git-log-fix	\
+	    --srcdir=$(srcdir)				\
 	    --since=$(gen_start_date) > $$cl.tmp &&	\
 	  mv -f $$cl.tmp $$cl;				\
 	fi