prosody, prosodyctl: Load loader directly from source directory This should ensure that loader.lua is loaded from the source directory and does the right thing when installed with `make install` There are currently three ways Prosody can be run: - Directly from the source directory, like `./prosody` - Installed with `make install` - Installed into Lua paths with e.g. dh-lua or luarocks In the first two cases, Lua search paths need to include the source directory and ensure that `require "prosody.util.json"` ends up loading `util/json.lua` relative to the installation (CFG_SOURCEDIR) or the source checkout. Finally, in the last case where Prosody resources are installed under the 'prosody.*' namespace in regular Lua search paths, then loader.lua should activate the compatibility mode that makes sure that both `require"util.json"` and `require"prosody.util.json"` both resolve to `(one path from of package.path)/prosody/util/json.lua`

local data = {}
local getinfo = debug.getinfo;
local function linehook(ev, li)
	local S = getinfo(2, "S");
	if S and S.source and S.source:match"^@" then
		local file = S.source:sub(2);
		local lines = data[file];
		if not lines then
			lines = {};
			data[file] = lines;
			for line in io.lines(file) do
				lines[#lines+1] = line;
			end
		end
		io.stderr:write(ev, " ", file, " ", li, " ", lines[li], "\n");
	end
end
debug.sethook(linehook, "l");