Revert "Re-add __USE_GNU for include of dlfcn.h which is required for definition of RTLD_DEFAULT"

Reconfigure is nessicary to pick up the correct definitions - the macro _is_ no longer needed as previously claimed

This reverts commit bcb483d.

Author: phausler

Diff for: closure/runtime.c

@@ -12,12 +12,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
-#if TARGET_OS_LINUX
-#define __USE_GNU
 #include <dlfcn.h>
-#else
-#include <dlfcn.h>
-#endif
 #if __has_include(<os/assumes.h>)
 #include <os/assumes.h>
 #else