testsuite: Fix concepts-using2.C failure on 32-bit targets [PR93907]

The test FAILs on 32-bit targets that don't have __int128 type.

2020-03-12  Jakub Jelinek  <jakub@redhat.com>

	PR c++/93907
	* g++.dg/cpp2a/concepts-using2.C (cc): Use long long instead of
	__int128 if __SIZEOF_INT128__ isn't defined.

gcc/testsuite/ChangeLog

+2020-03-12  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/93907
+	* g++.dg/cpp2a/concepts-using2.C (cc): Use long long instead of
+	__int128 if __SIZEOF_INT128__ isn't defined.
+
 2020-03-06  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/94074 - wrong modifying const object error for COMPONENT_REF.

gcc/testsuite/g++.dg/cpp2a/concepts-using2.C

@@ -15,7 +15,11 @@ template <typename b> using an = typename n<b>::e;
 template <typename> constexpr bool ao = c<true>::d;
 template <typename> constexpr bool i = c<1>::d;
 template <typename> concept bb = i<b>;
+#ifdef __SIZEOF_INT128__
 using cc = __int128;
+#else
+using cc = long long;
+#endif
 template <typename> concept cd = bb<cc>;
 template <typename bt> concept ce = requires { requires cd<bt>; };
 template <typename bt> concept h = ce<bt>;