Using lbasename ensures that the build path does not end up in the
module file.

Regtested on x86_64-pc-linux-gnu, committed to trunk. Will shortly
backport to the 6 and 7 branches as well.

2018-02-13  Alastair McKinstry  <alastair.mckinstry@sceal.ie>
	    Janne Blomqvist  <jb@gcc.gnu.org>

	* module.c (dump_module): Use lbasename to ensure that module
	files are reproducible.

Co-Authored-By: Janne Blomqvist <jb@gcc.gnu.org>

From-SVN: r257613