same fixes as in previous commit for gcc

src/lib/system/linux/gnuc/x86_64/SYSTEM.c0

@@ -20,7 +20,7 @@
 #include "varargs.h"
 #endif
 
-extern void *malloc(long size);
+extern void *malloc(unsigned long size);
 extern void exit(int status);
 
 void (*SYSTEM_Halt)();

src/lib/system/linux/gnuc/x86_64/SYSTEM.h

@@ -13,8 +13,8 @@ uses double # as concatenation operator
 
 #include <alloca.h>
 
-extern void *memcpy(void *dest, const void *src, long n);
-extern void *malloc(long size);
+extern void *memcpy(void *dest, const void *src, unsigned long n);
+extern void *malloc(unsigned long size);
 extern void exit(int status);
 
 #define export