--- Makefile
+++ Makefile
@@ -10,7 +10,7 @@
   RELEASE_STRING := $(RELEASE_NAME)-$(RELEASE_MAJOR).$(RELEASE_MINOR).$(RELEASE_SUBLEVEL)$(RELEASE_EXTRALEVEL)
 
   CFLAGS = $(EXTRA_CFLAGS) -DEFIBOOTMGR_VERSION=\"$(RELEASE_MAJOR).$(RELEASE_MINOR).$(RELEASE_SUBLEVEL)$(RELEASE_EXTRALEVEL)\" \
-	    -Wall -g -D_FILE_OFFSET_BITS=64
+	    -Wall -g -D_FILE_OFFSET_BITS=64 -std=gnu89
 
   MODULES := src