Gimplify va_arg ap based on do_deref

2015-05-13  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/66010
	* gimplify.h (gimplify_va_arg_internal): Remove declaration.
	* gimplify.c (gimplify_va_arg_internal): Remove and inline into ...
	* tree-stdarg.c (expand_ifn_va_arg_1): ... here.  Choose between lval
	and rval based on do_deref.

From-SVN: r223120