make MREMAP_MOVE_THRESHOLD into size_t constant

This avoids a clang-tidy warning and is a bit cleaner.

h_malloc.c

@@ -27,7 +27,7 @@
 
 #define SLAB_QUARANTINE (SLAB_QUARANTINE_RANDOM_LENGTH > 0 || SLAB_QUARANTINE_QUEUE_LENGTH > 0)
 #define REGION_QUARANTINE (REGION_QUARANTINE_RANDOM_LENGTH > 0 || REGION_QUARANTINE_QUEUE_LENGTH > 0)
-#define MREMAP_MOVE_THRESHOLD (32 * 1024 * 1024)
+#define MREMAP_MOVE_THRESHOLD ((size_t)32 * 1024 * 1024)
 
 static_assert(sizeof(void *) == 8, "64-bit only");