Add missing test files.

(cherry picked from commit 3a00b16)

locale/tst-duplocale.c

@@ -0,0 +1,14 @@
+#include <locale.h>
+#include <stdio.h>
+
+static int
+do_test (void)
+{
+  locale_t d = duplocale (LC_GLOBAL_LOCALE);
+  if (d != (locale_t) 0)
+    freelocale (d);
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

locale/tst-locname.c

@@ -0,0 +1,20 @@
+#include <langinfo.h>
+#include <locale.h>
+#include <stdio.h>
+#include <string.h>
+
+static int
+do_test (void)
+{
+  const char *s = nl_langinfo (_NL_LOCALE_NAME (LC_CTYPE));
+  if (s == NULL || strcmp (s, "C") != 0)
+    {
+      printf ("incorrect locale name returned: %s, expected \"C\"\n", s);
+      return 1;
+    }
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"