re PR c/52290 (internal compiler error: tree check: expected function_decl, have var_decl in start_function, at c-decl.c:7712)

	PR c/52290
	* c-decl.c (start_function): Exit early if decl1 is not FUNTION_DECL.

testsuite/ChangeLog:

	PR c/52290
	* gcc.dg/noncompile/pr52290.c: New test.

From-SVN: r184511