Fix github mac/windows builds by fixing Lua fetch target to HTTPS

As extra reinforcement, pass -L to curl.

Upstream NetHack has made a bunch of changes to Makefile.top to fix
fetch-lua but merging them all in is too much work right now; when
vanilla is next merged the change from this commit will be dropped when
it conflicts with theirs.

sys/unix/Makefile.top

@@ -314,7 +314,7 @@ fetch-lua: fetch-Lua
 
 fetch-Lua:
 	( mkdir -p lib && cd lib && \
-	  curl -R -O http://www.lua.org/ftp/lua-$(LUA_VERSION).tar.gz && \
+	  curl -R -O -L https://www.lua.org/ftp/lua-$(LUA_VERSION).tar.gz && \
 	  tar zxf lua-$(LUA_VERSION).tar.gz && \
 	  rm -f lua-$(LUA_VERSION).tar.gz )
 # remove include/nhlua.h in case it was created for some other Lua version