problem(s) with extractbb and extractbb.lua recently introduced

[Karl Berry]

Hi Bruno - thanks for all your efforts.

            script_path = io.popen("readlink -f '"..script_path.."'",

Unfortunately, the readlink and realpath commands are not portable (enough).

I'm guessing/hoping Lua has some way to resolve symlinks and get to the
real path. Leaving it for Max, since I have no real knowledge here.
--thanks again, karl.