diff --git a/tools/mm/Makefile b/tools/mm/Makefile
index 9860622cbb15..6c1da51f4177 100644
--- a/tools/mm/Makefile
+++ b/tools/mm/Makefile
@@ -8,8 +8,8 @@ TARGETS=page-types slabinfo page_owner_sort
 LIB_DIR = ../lib/api
 LIBS = $(LIB_DIR)/libapi.a
 
-CFLAGS = -Wall -Wextra -I../lib/
-LDFLAGS = $(LIBS)
+CFLAGS += -Wall -Wextra -I../lib/
+LDFLAGS += $(LIBS)
 
 all: $(TARGETS)