* tree.h (struct tree_decl): Add malloc_flag.
	(DECL_IS_MALLOC): Define.
	* c-common.c (attrs): Add A_MALLOC attribute.
	(init_attributes): Add this attribute to the table.
	(decl_attributes): Handle malloc attribute.
	* calls.c (special_function_p): Check for the malloc attribute.
	* extend.texi (Function Attributes): Document malloc attribute.

From-SVN: r30689