bugfixes, change types.h to be linux abi, stat system call

src/sys/mm/alloc.c

@@ -11,7 +11,7 @@ void* alloc(size_t size){
 }
 
 void free(void* addr){
-	if(pageallocator_free(addr))
+	if(!pageallocator_free(addr))
 		slab_free(addr);
 }
 

src/sys/mm/slab.c

@@ -56,7 +56,8 @@ size_t slab_getentrysize(void* addr){
 }
 
 static void free(void* addr){
-	
+	if(addr == 0)
+		return;
 	// align down to page size
 	
 	slab_t *slab = (size_t)addr & ~(0xFFF);