PR libstdc++/88607 add tests using -finput-charset=ascii

This verifies that the <bits/extc++.h> header can be compiled with ASCII
as the input character set.

	PR libstdc++/88607
	* testsuite/17_intro/headers/c++1998/charset.cc: New test.
	* testsuite/17_intro/headers/c++2011/charset.cc: New test.
	* testsuite/17_intro/headers/c++2014/charset.cc: New test.
	* testsuite/17_intro/headers/c++2017/charset.cc: New test.
	* testsuite/17_intro/headers/c++2020/charset.cc: New test.

From-SVN: r267607

libstdc++-v3/ChangeLog

+2019-01-06  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/88607
+	* testsuite/17_intro/headers/c++1998/charset.cc: New test.
+	* testsuite/17_intro/headers/c++2011/charset.cc: New test.
+	* testsuite/17_intro/headers/c++2014/charset.cc: New test.
+	* testsuite/17_intro/headers/c++2017/charset.cc: New test.
+	* testsuite/17_intro/headers/c++2020/charset.cc: New test.
+
 2019-01-05  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/bits/fs_fwd.h (__file_clock): Define new clock.

libstdc++-v3/testsuite/17_intro/headers/c++1998/charset.cc

+// { dg-options "-finput-charset=ascii" }
+// { dg-do compile }
+
+#include <bits/extc++.h>

libstdc++-v3/testsuite/17_intro/headers/c++2011/charset.cc

+// { dg-options "-finput-charset=ascii" }
+// { dg-do compile }
+
+#include <bits/extc++.h>

libstdc++-v3/testsuite/17_intro/headers/c++2014/charset.cc

+// { dg-options "-finput-charset=ascii" }
+// { dg-do compile }
+
+#include <bits/extc++.h>

libstdc++-v3/testsuite/17_intro/headers/c++2017/charset.cc

+// { dg-options "-finput-charset=ascii" }
+// { dg-do compile }
+
+#include <bits/extc++.h>

libstdc++-v3/testsuite/17_intro/headers/c++2020/charset.cc

+// { dg-options "-finput-charset=ascii" }
+// { dg-do compile }
+
+#include <bits/extc++.h>