diff --git a/extern/decNumber/Makefile b/extern/decNumber/Makefile
index 253e34c1806..b6d2121c29d 100644
--- a/extern/decNumber/Makefile
+++ b/extern/decNumber/Makefile
@@ -2,7 +2,7 @@ LIBRARY=libdecFloat$(CROSS).a
 
 $(LIBRARY):		$(wildcard *.c) $(wildcard *.h) Makefile
 	$(RM) -f *.o
-	$(CC) $(CROSS_FLAGS) -c -O3 -fPIC $(subst decCommon.c,,$(subst decBasic.c,,$(wildcard *.c)))
+	$(CC) $(CROSS_FLAGS) $(CFLAGS) -c -O3 -fPIC $(subst decCommon.c,,$(subst decBasic.c,,$(wildcard *.c)))
 	$(AR) crs $(LIBRARY) *.o
 	$(RM) -f *.o