Move definition of _GNU_SOURCE up

Author: fangerer

graalpython/com.oracle.graal.python.cext/include/pyconfig.h

@@ -41,6 +41,11 @@
 #ifndef Py_PYCONFIG_H
 #define Py_PYCONFIG_H
 
+/* Enable GNU extensions on systems that have them. */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
+
 // required for __UINT32_MAX__ etc.
 #include <limits.h>
 
@@ -69,11 +74,6 @@
 /* Define to 1 if you have the ANSI C header files. */
 #define STDC_HEADERS 1
 
-/* Enable GNU extensions on systems that have them. */
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE 1
-#endif
-
 # ifndef UINT_MAX
 #define UINT_MAX __UINT32_MAX__
 #endif