configure --help works
$ cd $TESTDIR/../../..
$ touch $TMP/mozconfig
$ export MOZCONFIG=$TMP/mozconfig
$ ./configure --help 2>& 1 | head -n 7
Adding configure options from */tmp/mozconfig (glob)
checking for vcs source checkout... hg
Usage: configure.py [options]
Options: [defaults in brackets after descriptions]
--help print this message