Merge libphobos upstream version 2.076.1

Merge libphobos upstream version 2.076.1

Updated the library version to 76:3:0.

libphobos/ChangeLog:

2018-11-28  Iain Buclaw  <ibuclaw@gdcproject.org>

	* Makefile.in: Rebuild.
	* configure: Rebuild.
	* configure.ac (DRUNTIME_SOVERSION): Remove.
	(PHOBOS_SOVERSION): Remove.
	(libtool_VERSION): Add.
	* libdruntime/Makefile.am: Use libtool_VERSION.
	* libdruntime/Makefile.in: Rebuild.
	* src/Makefile.am: Use libtool_VERSION.
	* src/Makefile.in: Rebuild.
	* testsuite/Makefile.in: Rebuild.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@266572 138bc75d-0d04-0410-961f-82ee72b054a4