--- a/gdt/Makefile
+++ b/gdt/Makefile
@@ -27,7 +27,7 @@ include $(GSH_BASE_DIR)/makedefs
 
 INCLUDES += -I$(GSH_BASE_DIR)
 
-CFLAGS += -std=c99
+GDT_CFLAGS = $(CFLAGS) -std=c99
 
 GDT_SRC_FILES = char_buffer.c gdt_index.c gdt_table.c
 GDT_OBJ_FILES := $(GDT_SRC_FILES:%.c=%.o)
@@ -36,7 +36,7 @@ DEP_FILES := $(GDT_SRC_FILES:%.c=.deps/%.P)
 
 DEPS_MAGIC := $(shell mkdir .deps > /dev/null 2>&1 || :)
 
-COMPILE = $(CC) $(CFLAGS) $(LUA_CFLAGS) $(DEFS) $(INCLUDES)
+COMPILE = $(CC) $(GDT_CFLAGS) $(LUA_CFLAGS) $(DEFS) $(INCLUDES)
 
 TARGETS = libgdt.a