Merge tag 'v2.5.1_rc2'

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