LibC: Fix some headers to make gcc build again

libc/include/limits.h

@@ -11,12 +11,6 @@ __BEGIN_DECLS
 //        glibc seems to only define numerical
 //        and posix constants
 
-#if defined __GNUC__ && !defined _GCC_LIMITS_H_
-	#include_next <limits.h>
-#else
-	#error "unsupported compiler"
-#endif
-
 __END_DECLS
 
 #endif

libc/include/sys/mman.h

@@ -15,6 +15,7 @@ __BEGIN_DECLS
 #define MAP_FIXED		0x01
 #define MAP_PRIVATE		0x02
 #define MAP_SHARED		0x04
+#define MAP_ANONYMOUS	0x08
 
 #define MS_ASYNC		0x01
 #define MS_INVALIDATE	0x02