gcc/ChangeLog

	* defaults.h (ASM_OUTPUT_START_FUNCTION_HEADER): New hook function.
	(ASM_OUTPUT_START_FUNCTION_FOOTER): Ditto.
	* varasm.c (assemble_start_function): Call new hook at start of
	function.
	(assemble_end_function): Call new hook at end of function.
	* doc/tm.texi.in: Document new hook functions.