--- include/string.h.old	2009-09-04 09:18:54.000000000 +0200
+++ include/string.h	2009-09-04 09:19:41.000000000 +0200
@@ -43,7 +43,9 @@
 #ifdef __MSW__
 extern int strcasecmp(const char *s1, const char *s2);
 #endif
+#ifndef _GNU_SOURCE
 extern char *strcasestr(const char *haystack, const char *needle);
+#endif
 extern int strpfx(const char *s, const char *pfx);
 extern int strcasepfx(const char *s, const char *pfx);