lualoader config: don't call loader.getenv() as much

We don't actually need to fetch loader_conf_files as much as we do; we've
already fetched it once at the beginning, we only really need to fetch it
again after each file we've processed. If it changes, then we can stash that
off into our local prefiles.

While here, drop a note about the recursion so that I stop trying to
change it. It may very well make redundant some of the work we're doing, but
that's OK.

MFC after:	3 days

stand/lua/config.lua

@@ -343,13 +343,12 @@ end
 local function readConfFiles(loaded_files)
 	local f = loader.getenv("loader_conf_files")
 	if f ~= nil then
+		local prefiles = f
 		for name in f:gmatch("([%w%p]+)%s*") do
 			if loaded_files[name] ~= nil then
 				goto continue
 			end
 
-			local prefiles = loader.getenv("loader_conf_files")
-
 			print("Loading " .. name)
 			-- These may or may not exist, and that's ok. Do a
 			-- silent parse so that we complain on parse errors but
@@ -361,7 +360,12 @@ local function readConfFiles(loaded_files)
 			loaded_files[name] = true
 			local newfiles = loader.getenv("loader_conf_files")
 			if prefiles ~= newfiles then
+				-- Recurse; process the new files immediately.
+				-- If we come back and it turns out we've
+				-- already loaded the rest of what was in the
+				-- original loader_conf_files, no big deal.
 				readConfFiles(loaded_files)
+				prefiles = newfiles
 			end
 			::continue::
 		end