build: improve default build for non-gcc

Dagobert Michelsen reported that in a setup that uses git to
track patches on top of the distributed tarball, we ended up
having configure defaults that did not play nicely with the
Sun Studio 12.3 compiler.  Gnulib has fixed the problems with
detecting (un-)supported compiler flags, and additionally we
can use a better witness file of whether we are likely to be
a developer where it is worth enabling warnings by default.

* gnulib: Update to latest gnulib.
* configure.ac (gl_WARN_ADD): Drop flags now guaranteed by gnulib.
(--enable-gcc-warnings): Set default based on a tarball-only file,
rather than whether .git exists.
* THANKS: Update.

Signed-off-by: Eric Blake <eblake@redhat.com>
build: fix regression for DragonFly BSD

Fixes an issue reported by GW:
https://lists.gnu.org/archive/html/bug-m4/2013-11/msg00000.html

* gnulib: Update to latest gnulib, for fpending fix.

Signed-off-by: Eric Blake <eblake@redhat.com>
maint: bump copyright year

* all files: Version control now has a commit in 2014.
* gnulib: Update to latest.

Signed-off-by: Eric Blake <eblake@redhat.com>
main: diagnose unsupported --word-regexp

The long option for -W (--word-regexp) was accepted without
ENABLE_CHANGEWORD defined.

* src/m4.c (long_options): Don't allow long option if short option
is rejected.
* THANKS: Add attribution.

Signed-off-by: Eric Blake <eblake@redhat.com>
doc: fix line-wrapped macro definitions

The html rendering of the manual ate a comma and inserted an
awkward line wrap for the "example" macro prototype:
https://www.gnu.org/software/m4/manual/m4-1.4.17/html_node/Manual.html

As documented in autoconf, use of @c does not work for macros
which are designed for inline use within @deffn and friends.
http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=a357718

* doc/m4.texi: Drop bogus @c.
Reported by Marijn Schouten, fix by Patrice Dumas copied from
autoconf code base.

Signed-off-by: Eric Blake <eblake@redhat.com>
bootstrap: sync with upstream.

* gl/build-aux/bootstrap.in, gl/build-aux/extract-trace,
gl/build-aux/funclib.sh, gl/build-aux/inline-source,
gl/build-aux/options-parser: Sync with upstream.
* bootstrap: Regenerate.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: append $EXEEXT suffix to /bin/sh.

Without $EXEEXT, /bin/sh cannot be located on OS/2.
* configure.ac (with_syscmd_shell): append $EXEEXT suffix to /bin/sh.
* THANKS: Add KO Myung-Hun.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: add -Zargs-resp to LDFLAGS on OS/2.

-Zargs-resp enables a response file support on OS/2.
* configure.ac (OS2_LDFLAGS): Add -Zargs-resp on *-*-os2*.
* src/Makefile.am (AM_LDFLAGS): Add OS2_LDFLAGS.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
m4: fdopen() with a text mode explicitly on OS/2.

On OS/2 kLIBC, fdopen() creates a stream in a mode of a file
descriptor. So specify "t" to open a stream in a text mode explicitly
on OS/2.
* src/builtin.c (m4_esyscmd): fdopen() in a text mode on OS/2.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>