Reverse debugging for PowerPC.

Reverse debugging for PowerPC.

gdb/ChangeLog

	Backport from mainline:

	* configure.tgt (powerpc*-*-linux): Add linux-record.o to
	gdb_target_obs.
	(ppc_linux_record_tdep, ppc64_linux_record_tdep): New for linux syscall
	record.
	(ppc_canonicalize_syscall, ppc_linux_syscall_record,
	ppc_linux_record_signal, ppc_init_linux_record_tdep): New functions.
	(ppc_linux_init_abi): Set process_record, process_record_signal.
	* ppc-tdep.h (struct gdbarch_tdep): Add ppc_syscall_record and
	ppc_linux_record_tdep to gdbarch_tdep.
	(ppc_process_record): New declaration.
	* rs6000-tdep.c (ppc_record_vsr, ppc_process_record_op4,
	ppc_process_record_op19, ppc_process_record_op31,
	ppc_process_record_op59, ppc_process_record_op60,
	ppc_process_record_op63, ppc_process_record): New functions.

gdb/testsuite/ChangeLog

	Backport from mainline:

	* lib/gdb.exp (supports_process_record): Return true for
	powerpc*-*-linux*.
	(supports_reverse): Likewise.