* lib/fnmatch.in.h: Use the usual gnulib idioms for header file
replacements.
(FNM_*): Don't redefine if fnmatch exists and we are not overriding it.
(fnmatch): Use the usual gnulib idiom for function declarations. Enable
'posixcheck' warning.
* m4/fnmatch_h.m4: New file.
* m4/fnmatch.m4 (gl_FUNC_FNMATCH_POSIX): Require gl_FNMATCH_H. Remove
code that is moved to fnmatch_h.m4. When fnmatch does not exist, don't
bother testing whether it is working. Set HAVE_FNMATCH, REPLACE_FNMATCH
as appropriate.
* modules/fnmatch-h: New file.
* modules/fnmatch (Files): Remove lib/fnmatch.in.h.
(Dependencies): Add fnmatch-h. Remove extensions, snippet/*. Change
conditions.
(configure.ac): Test HAVE_FNMATCH and REPLACE_FNMATCH. Set module
indicator.
(Makefile.am): Remove code that is moved to fnmatch-h.
* modules/fnmatch-gnu (configure.ac): Test HAVE_FNMATCH and
REPLACE_FNMATCH.
* doc/posix-headers/fnmatch.texi: Mention the 'fnmatch-h' module.
* modules/posixcheck (Depends-on): Add fnmatch-h.