re PR c/30552 (gcc crashes when compiling examples with GNU statement expressions in VLAs (also involved: nested functions declared K&R-style))

	PR c/30552
	* c-decl.c (old_style_parameter_scope): New function.
	* c-parser.c (c_parser_postfix_expression): Check for statement
	expressions in old-style function parameter list declarations.
	* c-parser.h (old_style_parameter_scope): New extern declaration.

	PR c/30552
	* gcc.dg/noncompile/pr30552-1.c: New test.
	* gcc.dg/noncompile/pr30552-2.c: New test.
	* gcc.dg/noncompile/pr30552-3.c: New test.
	* gcc.dg/noncompile/pr30552-4.c: New test.

From-SVN: r259849