This patch syncs the regex implementation with gnulib (commit 0ee5212).
Only two changes in GLIBC regex testing are required:

  1. posix/bug-regex28.c: as previously discussed [1] the change of
     expected results on the pattern should be safe.

  2. posix/PCRE.tests: the ERE (a)|\1 is malformed (in the sense that
     the \1 doesn't mean anything) and although current GLIBC accepts
     it has undefined behavior.  This patch removes the specific test.

This sync contains some patches from thread 'Regex: Make libc regex
more usable outside GLIBC.' [2] which have been pushed upstream in
gnulib.  This patches also fixes some regex issues (BZ #23233,
BZ #21163, BZ #18986, BZ #13762) and I did not add testcases for
both #23233 and #13762 because I couldn't think a simple way to
trigger the expected failure path to trigger them.

Checked on x86_64-linux-gnu and i686-linux-gnu.

	[BZ #23233]
	[BZ #21163]
	[BZ #18986]
	[BZ #13762]
	* posix/Makefile (tests): Add bug-regex37 and bug-regex38.
	* posix/PCRE.tests: Remove invalid test.
	* posix/bug-regex28.c: Fix expected values for used syntax.
	* posix/bug-regex37.c: New file.
	* posix/bug-regex38.c: Likewise.
	* posix/regcomp.c: Sync with gnulib.
	* posix/regex.c: Likewise.
	* posix/regex.h: Likewise.
	* posix/regex_internal.c: Likewise.
	* posix/regex_internal.h: Likewise.
	* posix/regexec.c: Likewise.

[1] https://sourceware.org/ml/libc-alpha/2017-12/msg00807.html
[2] https://sourceware.org/ml/libc-alpha/2017-12/msg00237.html

	* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.

	next_last_offset.
	(struct re_dfa_t): Remove unused member states_alloc.
	* posix/regcomp.c (init_dfa): Don't initialize unused members.

2005-08-25  Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regexec.c (set_regs): Don't alloca with an unbounded size.

	alloca modernization/simplification for regex.
	* posix/regex.c: Remove portability cruft for alloca.  This no longer
	needs to be at the start of the file, and can be moved into
	regex_internal.h and simplified.
	* posix/regex_internal.h: Include <alloca.h>.
	(__libc_use_alloca) [!defined _LIBC]: New macro.
	* posix/regexec.c (build_trtable): Remove "#ifdef _LIBC",
	since the code now works outside glibc.

2005-09-06  Ulrich Drepper  <drepper@redhat.com>

	* include/regex.h: Remove use of _RE_ARGS.

2005-08-25  Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regexec.c (find_recover_state): Change "err" to "*err".

2005-08-24  Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regcomp.c (regerror): Pointer args are 'restrict',
	as per POSIX.
	* posix/regex.h (regerror): Likewise.
	* manual/pattern.texi (POSIX Regexp Compilation): Likewise.
	Similarly for regcomp and regexec.  Also, first 2 args of regexec
	and 2nd arg of regerror are const.

	* posix/regex.c: Do not include <sys/types.h>, as POSIX no longer
	requires this.  (The code never needed it.)

2005-08-20  Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regexec.c (sift_states_bkref): re_node_set_insert returns
	int, not reg_errcode_t.

	* posix/regex_internal.c (calc_state_hash): Put 'inline' before type,
	since some broken compilers warn about it otherwise.

	* posix/regcomp.c (create_initial_state): Remove duplicate decl.

2005-08-20  Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regex.h (_RE_ARGS): Remove.  No longer needed, since we assume
	C89 or better.  All uses removed.

2005-09-06  Ulrich Drepper  <drepper@redhat.com>

	* posix/regex.c: Prevent using C++ compilers.

2005-08-19  Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regcomp.c (duplicate_node): Return new index, not an error
	code, and let the caller return REG_ESPACE if out of space.  This
	removes an uninitialied-variable warning with GCC 4.0.1, and also
	avoids taking the address of a local variable.  All callers
	changed.

2005-09-06  Ulrich Drepper  <drepper@redhat.com>

	* include/time.h (__strptime_internal): Rename parameter to avoid
	bogus compiler warning.

2005-08-19  Jim Meyering  <jim@meyering.net>

	* posix/regexec.c (proceed_next_node): Redo local variables to
	avoid GCC shadowing warnings.

2005-09-06  Ulrich Drepper  <drepper@redhat.com>

	* posix/regex_internal.c (re_acquire_state): Minor code rearrangement.
	(re_acquire_state_context): Likewise.

2005-08-19  Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regex_internal.c (re_string_realloc_buffers):
	(re_node_set_insert, re_node_set_insert_last, re_dfa_add_node):
	Rename local variables to avoid GCC shadowing warnings.

2005-07-08  Eric Blake  <ebb9@byu.net>
            Paul Eggert  <eggert@cs.ucla.edu>

	* posix/regcomp.c (init_dfa): Store __btowc value in wint_t, not
	wchar_t.  Remove now-unnecessary cast.
	(build_range_exp): Likewise.