testsuite/newlib.wctype: Check wctype for __WCHAR_MAX__

__WCHAR_MAX__ shouldn't match any isw* functions. On 2-byte wchar_t
systems, it should be 0xffff which isn't used. On 4-byte wchar_t
systems, it should be 0xffffffff, which is well outside the range of
valid Unicode code points.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

newlib/testsuite/newlib.wctype/tiswctype.c

@@ -57,5 +57,9 @@ int main(void)
   x = wctype ("unknown");
   CHECK (x == 0);
 
+  CHECK(!iswprint((wint_t) __WCHAR_MAX__));
+  CHECK(!iswcntrl((wint_t) __WCHAR_MAX__));
+  CHECK(!iswgraph((wint_t) __WCHAR_MAX__));
+
   exit (0);
 }