ORIENT: avoid "expression has no effect" warning

The warning "right-hand operand of comma expression has no effect
[-Wunused-value]" crops up with -Wall in cases where ORIENT is called
without checking or assigning its value.

Explicitely void the expression in these cases to avoid the warning.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

newlib/libc/stdio/fwide.c

@@ -58,7 +58,7 @@ _fwide_r (struct _reent *ptr,
 
   _newlib_flockfile_start (fp);
   if (mode != 0) {
-    ORIENT (fp, mode);
+    (void) ORIENT (fp, mode);
   }
   if (!(fp->_flags & __SORD))
     ret = 0;

newlib/libc/stdio/open_memstream.c

@@ -367,7 +367,7 @@ internal_open_memstream_r (struct _reent *ptr,
   fp->_flags |= __SL64;
 #endif
   fp->_close = memcloser;
-  ORIENT (fp, wide);
+  (void) ORIENT (fp, wide);
   _newlib_flockfile_end (fp);
   return fp;
 }

newlib/libc/stdio/ungetwc.c

@@ -82,7 +82,7 @@ _ungetwc_r (struct _reent *ptr,
   size_t len;
 
   _newlib_flockfile_start (fp);
-  ORIENT (fp, 1);
+  (void) ORIENT (fp, 1);
   if (wc == WEOF)
     wc = WEOF;
   else if ((len = _wcrtomb_r(ptr, buf, wc, &fp->_mbstate)) == (size_t)-1)