diff --git a/sys/unix/Makefile.top b/sys/unix/Makefile.top
index 046cf4844..136e6997e 100644
--- a/sys/unix/Makefile.top
+++ b/sys/unix/Makefile.top
@@ -125,7 +125,7 @@ RECOVERBIN = recover
 LUAHEADERS ?= lib/lua-$(LUA_VERSION)/src
 LUATESTTARGET ?= $(LUAHEADERS)/lua.h
 LUATOP = $(LUAHEADERS)
-LUAMAKEFLAGS = CC='$(TARGET_CC)' SYSCFLAGS='$(SYSCFLAGS)'
+LUAMAKEFLAGS ?= CC='$(TARGET_CC)' SYSCFLAGS='$(SYSCFLAGS)'
 LUA2NHTOP ?= ../../..
 LUABASELIB ?= liblua-$(LUA_VERSION).a
 LUATOPLIB ?= lib/lua/$(LUABASELIB)