--- a/src/video/SDL_video.c	Tue Oct 30 12:30:02 2012 -0700
+++ b/src/video/SDL_video.c	Tue Oct 30 12:31:26 2012 -0700
@@ -2841,8 +2841,11 @@
     return SDL_FALSE;
 }
 
+#if SDL_VIDEO_DRIVER_COCOA
+#include "cocoa/SDL_cocoamessagebox.h"
+#endif
 #if SDL_VIDEO_DRIVER_X11
-extern int X11_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *buttonid);
+#include "x11/SDL_x11messagebox.h"
 #endif
 
 int
@@ -2860,6 +2863,11 @@
     }
 
     /* It's completely fine to call this function before video is initialized */
+#if SDL_VIDEO_DRIVER_COCOA
+    if (Cocoa_ShowMessageBox(messageboxdata, buttonid) == 0) {
+        return 0;
+    }
+#endif
 #if SDL_VIDEO_DRIVER_X11
     if (X11_ShowMessageBox(messageboxdata, buttonid) == 0) {
         return 0;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/cocoa/SDL_cocoamessagebox.h	Tue Oct 30 12:31:26 2012 -0700
@@ -0,0 +1,29 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#if SDL_VIDEO_DRIVER_COCOA
+
+extern int Cocoa_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *buttonid);
+
+#endif /* SDL_VIDEO_DRIVER_COCOA */
+
+/* vi: set ts=4 sw=4 expandtab: */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/cocoa/SDL_cocoamessagebox.m	Tue Oct 30 12:31:26 2012 -0700
@@ -0,0 +1,72 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#if SDL_VIDEO_DRIVER_COCOA
+
+#include "SDL.h"
+#include "SDL_cocoavideo.h"
+
+
+/* Display a Cocoa message box */
+int
+Cocoa_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *buttonid)
+{
+    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+
+    NSAlert* alert = [[NSAlert alloc] init];
+
+    if (messageboxdata->flags & SDL_MESSAGEBOX_ERROR) {
+        [alert setAlertStyle:NSCriticalAlertStyle];
+    } else if (messageboxdata->flags & SDL_MESSAGEBOX_WARNING) {
+        [alert setAlertStyle:NSWarningAlertStyle];
+    } else {
+        [alert setAlertStyle:NSInformationalAlertStyle];
+    }
+
+    [alert setMessageText:[[NSString alloc] initWithUTF8String:messageboxdata->title]];
+    [alert setInformativeText:[[NSString alloc] initWithUTF8String:messageboxdata->message]];
+
+    const SDL_MessageBoxButtonData *buttons = messageboxdata->buttons;
+    int i;
+    for (i = 0; i < messageboxdata->numbuttons; ++i) {
+        NSButton *button = [alert addButtonWithTitle:[[NSString alloc] initWithUTF8String:buttons[i].text]];
+        if (buttons[i].flags & SDL_MESSAGEBOX_BUTTON_RETURNKEY_DEFAULT) {
+            [button setKeyEquivalent:@"\r"];
+        } else if (buttons[i].flags & SDL_MESSAGEBOX_BUTTON_ESCAPEKEY_DEFAULT) {
+            [button setKeyEquivalent:@"\033"];
+        } else {
+            [button setKeyEquivalent:@""];
+        }
+    }
+
+    NSInteger clicked = [alert runModal];
+    clicked -= NSAlertFirstButtonReturn;
+    *buttonid = buttons[clicked].buttonid;
+
+    [pool release];
+
+    return 0;
+}
+
+#endif /* SDL_VIDEO_DRIVER_COCOA */
+
+/* vi: set ts=4 sw=4 expandtab: */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/x11/SDL_x11messagebox.h	Tue Oct 30 12:31:26 2012 -0700
@@ -0,0 +1,28 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#if SDL_VIDEO_DRIVER_X11
+
+extern int X11_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *buttonid);
+
+#endif /* SDL_VIDEO_DRIVER_X11 */
+
+/* vi: set ts=4 sw=4 expandtab: */