Fix warnings in fwscanf / rewind tests.

This patch fixes "set but not used" warnings in the tests
libio/bug-rewind.c and libio/bug-rewind2.c by checking the return
values from fwscanf and making the tests fail if those values aren't
as expected.

Tested for x86_64.

	* libio/bug-rewind.c (do_test): Check fwscanf return values.
	* libio/bug-rewind2.c (do_test): Likewise.

ChangeLog

@@ -1,5 +1,8 @@
 2014-11-26  Joseph Myers  <joseph@codesourcery.com>
 
+	* libio/bug-rewind.c (do_test): Check fwscanf return values.
+	* libio/bug-rewind2.c (do_test): Likewise.
+
 	* debug/test-stpcpy_chk-ifunc.c: Remove file.
 	* debug/test-strcpy_chk-ifunc.c: Likewise.
 	* wcsmbs/test-wcschr-ifunc.c: Likewise.

libio/bug-rewind.c

@@ -52,9 +52,19 @@ do_test (void)
 
   rewind (fptr);
   ret1 = fwscanf (fptr, L"%c%c", &arg1, &arg2);
+  if (ret1 != 2)
+    {
+      printf ("first fwscanf returned %d, expected 2\n", ret1);
+      return 3;
+    }
 
   rewind (fptr);
   ret2 = fwscanf (fptr, L"%c%n%c", &arg1, &num, &arg2);
+  if (ret2 != 2)
+    {
+      printf ("second fwscanf returned %d, expected 2\n", ret2);
+      return 4;
+    }
 
   if (arg2 != 'd')
     {

libio/bug-rewind2.c

@@ -45,6 +45,11 @@ do_test (void)
 
       rewind (fp);
       ret = fwscanf (fp, L"%c", dummy);
+      if (ret != 1)
+	{
+	  printf ("fwscanf returned %d, expected 1\n", ret);
+	  result = 1;
+	}
 
       printf ("current pos = %ld\n", ftell (fp));
       if (ftell (fp) != 1)