* config/arm/arm.c (arm_compute_static_chain_stack_bytes): New
	function.
	(arm_compute_initial_elimination_offset): Use it.
	(arm_compute_save_reg_mask): Include static chain save slot when
	calculating alignment.
	(arm_get_frame_offsets): Ditto.
	(thumb1_compute_save_reg_mask): Ensure we have a low register saved
	that we can use to decrement the stack when the stack decrement
	could be too big for an immediate value in a single insn.
	(thumb1_expand_prologue): Avoid using r12 for stack decrement.

From-SVN: r138327