fix optimization for GNU memory management

src/memory.c

@@ -736,7 +736,6 @@ TR_malloc(size_t size)
 {
 	struct memSegment * seg   = NULL;
 	long                psize = sysconf(_SC_PAGESIZE);
-	size_t              check;
 
 	size += sizeof(struct memSegment);
 
@@ -746,12 +745,17 @@ TR_malloc(size_t size)
 			size = ((size / psize) + 1) * psize;
 		}
 	} else {
-		check = size >> 1;
-		check = (size | check) - check;
+		if (size < 8) {
+			size = 8;
+		} else {
+			size_t check = size;
+			size_t mask  = 1;
+
+			while (check >>= 1) {
+				mask = (mask << 1) | 1;
+			}
 
-		if (check != size) {
-			// size is not a power of 2 so bring it to one.
-			size = ((size << 1) | size) - size;
+			size = (size << 1) & ~mask;
 		}
 	}