expr.c (expand_expr): Use unsave lang hook.

	* expr.c (expand_expr): Use unsave lang hook.
	* langhooks-def.h (LANG_HOOKS_UNSAVE): New.
	(LANG_HOOKS_INITIALIZER): Update.
	* langhooks.h (struct lang_hooks): New hook unsave.
	* tree.c (lang_unsave, lang_unsave_expr_now): Remove.
	(unsave_expr_1): Remove unused lang_unsave_expr_now.
	(unsave_expr_now_r): Rename lhd_unsave.  Update. Return input.
	(unsave_expr_now): Remove.
	* tree.h (unsave_expr_now, lang_unsave,
	lang_unsave_expr_now): Remove.
	(lhd_unsave): New.
cp:
	* cp-lang.c (LANG_HOOKS_UNSAVE): Redefine.
	* cp-tree.h (cxx_unsave): New.
	* tree.c (cp_unsave): Rename cxx_unsave, update prototype.
	(init_tree): Update.

From-SVN: r50449