RS6000: Fix PR 77359: Properly align local variables in functions calling alloca.

RS6000: Fix PR 77359: Properly align local variables in functions calling alloca.

gcc/ChangeLog:

2016-11-18  Dominik Vogt  <vogt@linux.vnet.ibm.com>

	* config/rs6000/rs6000.c (rs6000_stack_info): PR/77359: Properly align
	local variables in functions calling alloca.  Also update the ASCII
	drawings
	* config/rs6000/rs6000.h (STARTING_FRAME_OFFSET, STACK_DYNAMIC_OFFSET):
	PR/77359: Likewise.
	* config/rs6000/aix.h (STARTING_FRAME_OFFSET, STACK_DYNAMIC_OFFSET):
	PR/77359: Copy AIX specific versions of the rs6000.h macros to aix.h.

From-SVN: r242589