backport: re PR libitm/57643 (libitm.c/reentrant.c hangs on POWER8 with HTM)

backport: re PR libitm/57643 (libitm.c/reentrant.c hangs on POWER8 with HTM)

	Backport from mainline
	2013-06-20  Torvald Riegel  <triegel@redhat.com>

	* query.cc (_ITM_inTransaction): Abort when using the HTM fastpath.
	(_ITM_getTransactionId): Same.
	* config/x86/target.h (htm_transaction_active): New.

	2013-06-20  Torvald Riegel  <triegel@redhat.com>

	PR libitm/57643
	* beginend.cc (gtm_thread::begin_transaction): Handle reentrancy in
	the HTM fastpath.

From-SVN: r208295