Update lib/regex from glibc via Gnulib

This syncs recent refactorings from glibc, and incorporates:
2018-10-15 libc-config: merge from glibc
2018-10-15 regex: depend on libc-config
* .gitignore: Do not ignore m4/_*.m4.
* lib/cdefs.h: New file, copied from Gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/libc-config.h, m4/__inline.m4: New files, copied from Gnulib.
* lib/regcomp.c, lib/regex.c, lib/regex_internal.c:
* lib/regex_internal.h, lib/regexec.c:
Copy from glibc via Gnulib.

1 files changed, 22 insertions, 0 deletions

diff --git a/m4/__inline.m4 b/m4/__inline.m4
new file mode 100644
index 00000000000..3d0c4798997
--- /dev/null
+++ b/m4/__inline.m4
@@ -0,0 +1,22 @@
+# Test for __inline keyword
+dnl Copyright 2017-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl___INLINE],
+[
+  AC_CACHE_CHECK([whether the compiler supports the __inline keyword],
+    [gl_cv_c___inline],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+         [[typedef int foo_t;
+           static __inline foo_t foo (void) { return 0; }]],
+         [[return foo ();]])],
+       [gl_cv_c___inline=yes],
+       [gl_cv_c___inline=no])])
+  if test $gl_cv_c___inline = yes; then
+    AC_DEFINE([HAVE___INLINE], [1],
+      [Define to 1 if the compiler supports the keyword '__inline'.])
+  fi
+])