diff --git a/sys/unix/Makefile.top b/sys/unix/Makefile.top
index 533c80a6d..1c8bdf54a 100644
--- a/sys/unix/Makefile.top
+++ b/sys/unix/Makefile.top
@@ -121,7 +121,7 @@ lib/lua-$(LUA_VERSION)/src/liblua.a: lib/lua-$(LUA_VERSION)/src/lua.h
 	( cd lib/lua-$(LUA_VERSION)/src \
 	  && make CC='$(CC)' SYSCFLAGS='$(SYSCFLAGS)' a && cd ../../.. )
 lib/lua/liblua.a: lib/lua-$(LUA_VERSION)/src/liblua.a
-	@( if [ ! -d lib/lua ] ; then mkdir -p lib/lua ; fi )
+	@( if test -d lib/lua ; then true ; else mkdir -p lib/lua ; fi )
 	cp lib/lua-$(LUA_VERSION)/src/liblua.a $@
 include/nhlua.h: $(TOPLUALIB)
 	echo '/* nhlua.h - generated by top Makefile */' > $@
@@ -286,8 +286,9 @@ fetch-Lua:
 	  curl -R -O http://www.lua.org/ftp/lua-$(LUA_VERSION).tar.gz && \
 	  tar zxf lua-$(LUA_VERSION).tar.gz && \
 	  rm -f lua-$(LUA_VERSION).tar.gz )
-#if we just fetched lua, force include/nhlua.h to be built based on it
-	-rm include/nhlua.h
+# remove include/nhlua.h in case it was created for some other Lua version
+	@( if test -f include/nhlua.h ; then \
+	     rm -f include/nhlua.h && echo 'rm include/nhlua.h' ; fi )
 
 # 'make update' can be used to install a revised version after making
 # customizations or such.  Unlike 'make install', it doesn't delete everything