* c-cppbuiltin.c (c_cpp_builtins): Define __cpp_variadic_using.

From-SVN: r244283

gcc/c-family/ChangeLog

+2017-01-10  Jason Merrill  <jason@redhat.com>
+
+	Implement P0195R2, C++17 variadic using.
+	* c-cppbuiltin.c (c_cpp_builtins): Define __cpp_variadic_using.
+
 2017-01-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR translation/79019

gcc/c-family/c-cppbuiltin.c

@@ -970,6 +970,7 @@ c_cpp_builtins (cpp_reader *pfile)
 	  cpp_define (pfile, "__cpp_noexcept_function_type=201510");
 	  cpp_define (pfile, "__cpp_template_auto=201606");
 	  cpp_define (pfile, "__cpp_structured_bindings=201606");
+	  cpp_define (pfile, "__cpp_variadic_using=201611");
 	}
       if (flag_concepts)
 	cpp_define (pfile, "__cpp_concepts=201507");

gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C

@@ -404,6 +404,12 @@
 #  error "__cpp_template_template_args != 201611"
 #endif
 
+#ifndef __cpp_variadic_using
+#  error "__cpp_variadic_using"
+#elif __cpp_variadic_using != 201611
+#  error "__cpp_variadic_using != 201611"
+#endif
+
 #ifdef __has_cpp_attribute
 
 #  if ! __has_cpp_attribute(maybe_unused)