*: add optimization barrier to all "G trick" locations

diff --git a/util-linux/fdisk.c b/util-linux/fdisk.c
index c98a74f..827ea21 100644
--- a/util-linux/fdisk.c
+++ b/util-linux/fdisk.c
@@ -309,7 +309,7 @@
 #define MBRbuffer       (G.MBRbuffer)
 #define ptes            (G.ptes)
 #define INIT_G() do { \
-	PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
+	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
 	sector_size = DEFAULT_SECTOR_SIZE; \
 	sector_offset = 1; \
 	g_partitions = 4; \