libphobos: Add subdir-objects to configure script.

Running autoreconf regenerates all files cleanly with autoconf2.69.

libphobos/ChangeLog:

2019-04-12  Iain Buclaw  <ibuclaw@gdcproject.org>

	* configure.ac (AM_INIT_AUTOMAKE): Add subdir-objects.
	* configure: Regenerate.
	* libdruntime/Makefile.in: Regenerate.

From-SVN: r270330
4 files changed