re PR tree-optimization/70144 (g++ ICE at -O1 and above on valid code on x86_64-linux-gnu in "copy_reference_ops_from_ref")

	PR c++/70144
	* cp-tree.h (magic_varargs_p): Return int instead of bool.
	* call.c (magic_varargs_p): Return int instead of bool, return 2 for
	Cilk+ reductions, otherwise 1 for magic varargs and 0 for normal
	varargs.
	(build_over_call): If magic_varargs_p == 2, call reject_gcc_builtin,
	if magic_varargs_p == 1, call decay_conversion
	instead of mark_type_use.  Don't store error_mark_node arguments to
	argarray, instead return error_mark_node.

	* c-c++-common/pr70144-1.c: New test.
	* c-c++-common/pr70144-2.c: New test.

From-SVN: r234297