diff --git a/Makefile b/Makefile
index dc675a0..1f53d40 100644
--- a/Makefile
+++ b/Makefile
@@ -118,3 +118,3 @@ $(LLVM_EXT_OBJ): $(LLVM_EXT_DIR)/llvm_ext.cc
 $(LIB_CRYSTAL_TARGET): $(LIB_CRYSTAL_OBJS)
-	ar -rcs $@ $^
+	$(AR) -rcs $@ $^