re PR middle-end/17813 (ada bootstrap failure on i486-linux)

re PR middle-end/17813 (ada bootstrap failure on i486-linux)

	PR middle-end/17813
	* dojump.c (discard_pending_stack_adjust): New function.
	(clear_pending_stack_adjust): Call it.
	* expr.h (discard_pending_stack_adjust): Declare it.
	* explow.c (emit_stack_save): Emit pending stack adjustments
	before saving the stack pointer.
	(emit_stack_restore): Discard pending stack adjustments before
	restoring the stack pointer.

Co-Authored-By: Roger Sayle <roger@eyesopen.com>
From-SVN: r89251