Improve checks for setmode()

As reported by Jonathan, OS X has setmode() that is something other
than what setmode() is on Win32.  So, limit invocation to Windows
platforms only.

configure.ac

@@ -55,8 +55,8 @@ dnl GOBJECT_INTROSPECTION_CHECK([0.9.0])
 dnl GTK_DOC_CHECK([1.15],[--flavour no-tmpl])
 
 # Functions and headers
-AC_CHECK_FUNCS(atexit mprotect sysconf getpagesize mmap setmode isatty)
-AC_CHECK_HEADERS(unistd.h sys/mman.h io.h)
+AC_CHECK_FUNCS(atexit mprotect sysconf getpagesize mmap isatty)
+AC_CHECK_HEADERS(unistd.h sys/mman.h)
 
 # Compiler flags
 AC_CANONICAL_HOST

util/options.cc

@@ -413,7 +413,7 @@ font_options_t::get_font (void) const
       /* read it */
       GString *gs = g_string_new (NULL);
       char buf[BUFSIZ];
-#ifdef HAVE_SETMODE
+#if defined(_WIN32) || defined(__CYGWIN__)
       setmode (fileno (stdin), _O_BINARY);
 #endif
       while (!feof (stdin)) {
@@ -557,7 +557,7 @@ output_options_t::get_file_handle (void)
   if (output_file)
     fp = fopen (output_file, "wb");
   else {
-#ifdef HAVE_SETMODE
+#if defined(_WIN32) || defined(__CYGWIN__)
     setmode (fileno (stdout), _O_BINARY);
 #endif
     fp = stdout;

util/options.hh

@@ -43,7 +43,7 @@
 #ifdef HAVE_UNISTD_H
 #include <unistd.h> /* for isatty() */
 #endif
-#ifdef HAVE_IO_H
+#if defined(_WIN32) || defined(__CYGWIN__)
 #include <io.h> /* for setmode() under Windows */
 #endif