Make gcc build script gn-compatible.

Make the build script position-independent (so it can be invoked from
a different directory, and with full support for specifying the output
directory location). Also, add an option to add a link to the
installation dir, to support easily locating output files.

Change-Id: I5abbd0cf9bc3c1b64a65fa5f31bbfb1bbfee4a0f
1 file changed