Add a function to hide the title bar on OS X

kitty/cocoa_window.m

@@ -0,0 +1,19 @@
+/*
+ * cocoa_window.m
+ * Copyright (C) 2017 Kovid Goyal <kovid at kovidgoyal.net>
+ *
+ * Distributed under terms of the GPL3 license.
+ */
+
+
+#include "data-types.h"
+#include <Cocoa/Cocoa.h>
+
+PyObject*
+cocoa_hide_titlebar(PyObject UNUSED *self, PyObject *window_id) {
+    NSView *native_view = (NSView*)PyLong_AsVoidPtr(window_id);
+    NSWindow* window = [native_view window];
+    [window setStyleMask:
+        [window styleMask] & ~NSTitledWindowMask];
+    Py_RETURN_NONE;
+}