Use setmode() instead of _setmode()

Looks like Cygwin / MSVC declare it that way, and it still works on
MinGW32 cross.

util/options.cc

diff --git a/util/options.cc b/util/options.cc
index 17ad8e6..c9deb0d 100644
--- a/util/options.cc
+++ b/util/options.cc
@@ -414,7 +414,7 @@
       GString *gs = g_string_new (NULL);
       char buf[BUFSIZ];
 #ifdef HAVE__SETMODE
-      _setmode (fileno (stdin), _O_BINARY);
+      setmode (fileno (stdin), _O_BINARY);
 #endif
       while (!feof (stdin)) {
 	size_t ret = fread (buf, 1, sizeof (buf), stdin);

util/options.hh

diff --git a/util/options.hh b/util/options.hh
index ad925b2..298a3f2 100644
--- a/util/options.hh
+++ b/util/options.hh
@@ -44,7 +44,7 @@
 #include <unistd.h> /* for isatty() */
 #endif
 #ifdef HAVE_IO_H
-#include <io.h> /* for _setmode() under Windows */
+#include <io.h> /* for setmode() under Windows */
 #endif
 
 #include <hb.h>