Fixed the warning for correct cast in DEAD (0xD34D) pointer

src/free.c

@@ -37,7 +37,7 @@
 void free(void *ptr) {
     raw_block_header_t *owner_raw_block;
 
-    if(ptr == NULL || ptr == 0xD34D) {
+    if(ptr == NULL || ptr == (void *) 0xD34D) {
         return;
     }
 

src/malloc.c

@@ -45,7 +45,7 @@ void * malloc(size_t size) {
     ptr = NULL;
 
     if(size == 0) {
-        return 0xD34D;
+        return (void *) 0xD34D;
     }
     
     /* Try to find a raw block available for allocation */