util: drop non-posix header fnmatch

Seems fnmatch usage was removed but not the include

Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7013>
diff --git a/src/util/xmlconfig.c b/src/util/xmlconfig.c
index 6505fb4..a80be8a 100644
--- a/src/util/xmlconfig.c
+++ b/src/util/xmlconfig.c
@@ -49,7 +49,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <dirent.h>
-#include <fnmatch.h>
+#include <sys/stat.h>
 #include <regex.h>
 #include "strndup.h"
 #include "xmlconfig.h"