re PR c/71574 (ICE on code with alloc_align attribute on x86_64-linux-gnu: in default_conversion, at c/c-typeck.c:2126)

	PR c/71574
	* c-common.c (handle_alloc_align_attribute): Also check FUNCTION_DECL.

	* c-c++-common/pr71574.c: New test.

From-SVN: r238859