Merge tag 'v2.5.1_rc2'

Bison 2.5.1_rc2.

* tag 'v2.5.1_rc2': (34 commits)
  Bison 2.5.1_rc2.
  doc: fixes.
  build: fix ChangeLog generation.
  c++: compute the header guards.
  skeletons: remove support for unused directive.
  lalr1.cc: improve Doxygen documentation.
  lalr1.cc: extract stack.hh.
  news: convert to double quotes.
  space changes.
  build: do not prototype flex-generated functions.
  build: fix ChangeLog generation.
  Bison 2.5.1_rc1.
  tests: save/restore Autotest special files when checking XML support.
  tests: AT_SAVE_SPECIAL_FILES / AT_RESTORE_SPECIAL_FILES.
  tests: honor TESTSUITEFLAGS in all the check targets.
  build: do not enable c++ warnings on 0 when nullptr is not supported.
  maint: update gnulib.
  build: config.in.h.
  build: move silent rules.
  glr.c: reduce variable scopes.
  maint: maintainer-release-check.
  maint: shush a syntax-check.
  maint: prefer "commit message" to "log entry".
  command line: fix minor leaks.
  maint: we no longer maintain the ChangeLog.
  maint: fix the generation of the synclines for bison's parser.
  maint: regen.
  maint: import the xmemdup0 gnulib module.
  maint: remove left-over gnulib modules.
  maint: ignore files imported by autopoint.
  build: AC_PROG_LEX: use more readable variable names.
  maint: regen src/parse-gram.[ch]
  maint: simplify parse-gram.y
  maint: s/strncpy/memcpy/, when equivalent

Conflicts:
	Makefile.am
	NEWS
	data/glr.c
	data/lalr1.cc
	data/stack.hh
	examples/rpcalc/local.mk
	src/flex-scanner.h
	src/getargs.c
	src/output.c
	src/parse-gram.c
	src/parse-gram.h
	src/parse-gram.y
	tests/Makefile.am
	tests/bison.in

README-hacking

@@ -15,25 +15,16 @@ First, if it is a large change, you must make sure they have signed
 the appropriate paperwork.  Second, be sure to add their name and
 email address to THANKS.
 
-** If a change fixes a test, mention the test in the ChangeLog entry.
+** If a change fixes a test, mention the test in the commit message.
 
 ** Bug reports
-If somebody reports a new bug, mention his name in the ChangeLog entry
+If somebody reports a new bug, mention his name in the commit message
 and in the test case you write.  Put him into THANKS.
 
 The correct response to most actual bugs is to write a new test case
 which demonstrates the bug.  Then fix the bug, re-run the test suite,
 and check everything in.
 
-** You may find it useful to install the git-merge-changelog merge driver:
-
-  http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/git-merge-changelog.c
-
-When following the generic installation instructions there, keep in mind that
-your clone of Bison's git repository already contains appropriate
-.gitattributes files, and running Bison's bootstrap script will make the
-necessary changes to .git/config.
-
 
 * Hacking
 
@@ -176,7 +167,7 @@ The autoconf files we use are currently:
         lib/m4sugar/m4sugar.m4
         lib/m4sugar/foreach.m4
 
-These files don't change very often in autoconf, so it should be
+These files don't change very often in Autoconf, so it should be
 relatively straight-forward to examine the differences in order to
 decide whether to update.
 
@@ -196,6 +187,9 @@ release:
 - Build with -DGNULIB_POSIXCHECK.  It suggests gnulib modules that can
   fix portability issues.
 
+- Check with `make syntax-check' if there are issues diagnosed by
+  gnulib.
+
 - run `make maintainer-check' which:
   - runs `valgrind -q bison' to run Bison under Valgrind.
   - runs the parsers under Valgrind.
@@ -213,6 +207,9 @@ release:
   Bison's included XSLT style sheets with the output of --report=all and
   --graph.
 
+- running `make maintainer-release-check' takes care of running
+  maintainer-check, maintainer-push-check and maintainer-xml-check.
+
 - Change tests/atlocal/CFLAGS to add your preferred options.  For
   instance, `-traditional' to check that the parsers are K&R.  Note
   that it does not make sense for glr.c, which should be ANSI,
@@ -260,16 +257,17 @@ occurrences of PACKAGE_COPYRIGHT_YEAR in configure.ac.
 The version number, *and* the date of the release (including for
 betas).
 
-** Update ChangeLog
-Should have an entry similar to `Version 1.49b.'.
+** Mention the release name in a commit message
+Should have an entry similar to `Version 2.3b.'.
 
 ** Tag the release
-Before Bison will build with the right version number, you must tag the release
-in git.  Do this after all other changes.  The command is similar to:
+Before Bison will build with the right version number, you must tag
+the release in git.  Do this after all other changes.  The command is
+similar to:
 
   git tag -a v2.3b
 
-The log message can be simply:
+The commit message can be simply:
 
   Bison 2.3b