tree.h (CONSTRUCTOR_NO_CLEARING): Define.

	* tree.h (CONSTRUCTOR_NO_CLEARING): Define.
	* tree-core.h (CONSTRUCTOR_NO_CLEARING): Document it.
	* tree.def (CONSTRUCTOR): Likewise.
	* doc/generic.texi (CONSTRUCTOR): Likewise.  Update description.
	* gimplify.c (gimplify_init_constructor): Do not clear the object when
	the constructor is incomplete and CONSTRUCTOR_NO_CLEARING is set.
ada/
	* gcc-interface/utils2.c (gnat_build_constructor): Also set the flag
	CONSTRUCTOR_NO_CLEARING on the constructor.

From-SVN: r204677