Pass build time CC make var down to dejagnu so the sysroot
is set correctly when gcc is built with --with-build-sysroot.

libitm/
2016-08-24  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	PR testsuite/71931
	* configure.ac: Add AC_CONFIG_FILES.
	* configure: Regenerated.
	* testuite/Makefile.am: Add rule for libitm-test-support.exp.
	* testuite/Makefile.in: Regenerated.
	* testuite/libitm-test-support.exp.in: New.
	* testuite/lib/libitm.exp (libitm_init): Use BUILD_CC.