Fix libgphobos.spec in the wrong place with --enable-version-specific-runtime-libs

Fix libgphobos.spec in the wrong place with --enable-version-specific-runtime-libs

libphobos/ChangeLog:

2018-11-01  Iain Buclaw  <ibuclaw@gdcproject.org>

	PR d/87827
	* Makefile.in: Rebuild.
	* configure: Rebuild.
	* configure.ac: Properly set MULTISUBDIR.
	* d_rules.am: Set toolexecdir and toolexeclibdir.
	* libdruntime/Makefile.in: Rebuild.
	* m4/druntime.m4 (DRUNTIME_INSTALL_DIRECTORIES): Add
	--enable-version-specific-runtime-libs.
	* src/Makefile.in: Rebuild.
	* testsuite/Makefile.in: Rebuild.

From-SVN: r265742