#!/usr/bin/env lua

--
-- Yoink
-- Run this script to link the executable with fewer direct dependencies.
--
-- You shouldn't call this directly; instead, use the configure script's
-- --enable-asneeded option and run make normally.  This isn't enabled by
-- default because there is the potential for runtime linking problems on
-- some platforms.  If you have a newer version of GCC, you should prefer
-- the --as-needed linker flag over this method, though they both should
-- accomplish the same thing.
--


-- List here any libraries that are known to not be needed on some
-- platform.
libraries = {
	"atk-1.0",
	"cairo",
	"fontconfig",
	"freetype",
	"gdk-x11-2.0",
	"gio-2.0",
	"glib-2.0",
	"gmodule-2.0",
	"ogg",
	"pango-1.0",
	"pangocairo-1.0",
	"pangoft2-1.0",
	"pthread",
	"vorbis"
}


-- We want to print only if verbose is set to true.
do
	local verbose	= os.getenv("verbose") == "true"
	local oldprint	= print

	print = function(...) if verbose then oldprint(unpack(arg)) end end
end


command		= arg[1]
removed		= {}

-- Get the link command as passed on the command-line.
for i,arg in ipairs(arg) do
	if i ~= 1 then
		command = string.format("%s %q", command, arg)
	end
end

original = command


-- Check for libraries which aren't needed for successful linking.
for i,library in ipairs(libraries) do
	local new_command = command:gsub("%s\"%-l"..library.."+\"%s", " ")
	if new_command ~= command then
		if os.execute(new_command.." >/dev/null 2>&1") == 0 then
			print("We DON'T need "..library)
			table.insert(removed, library)
			command = new_command
		else
			print("We DO need "..library)
		end
	end
end


-- Perform the final link.
if 0 < #removed and os.execute(command.." >/dev/null 2>&1") == 0 then
	local removed = table.concat(removed, ", ")
	print("Linked fine without some libraries: "..removed)
elseif os.execute(original.." >/dev/null 2>&1") == 0 then
	print("Linked with the original link command.")
else
	print("The link failed.  :-(")
	os.exit(1)
end