posix: Sync glob code with gnulib

It sync with gnulib commit 43ee1a6bf and fixes and use-after-free
bug (gnulib commit 717766da8926e36).

Checked on x86_64-linux-gnu.

posix/glob_pattern_p.c

@@ -17,7 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #ifndef _LIBC
-# include <config.h>
+# include <libc-config.h>
 #endif
 
 #include <glob.h>

posix/globfree.c

@@ -17,7 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #ifndef _LIBC
-# include <config.h>
+# include <libc-config.h>
 #endif
 
 #include <glob.h>