re PR middle-end/64766 (internal compiler error: tree check: expected block, have error_mark in lower_function_body, at gimple-low.c:122)

	PR c/64766
	* c-typeck.c (store_init_value): Don't overwrite DECL_INITIAL
	of FUNCTION_DECLs with error_mark_node.

	* gcc.dg/pr64766.c: New test.

From-SVN: r220152