Index: src/video/cocoa/cocoa_v.mm
===================================================================
--- src/video/cocoa/cocoa_v.mm	(revision 11498)
+++ src/video/cocoa/cocoa_v.mm	(working copy)
@@ -8,6 +8,7 @@
 
 #ifdef WITH_COCOA
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_3
 #include <AvailabilityMacros.h>
 
 #import <Cocoa/Cocoa.h>
@@ -233,9 +234,7 @@
 
 static CocoaSubdriver *QZ_CreateWindowSubdriver(int width, int height, int bpp)
 {
-	long sysVersion;
-
-	if (Gestalt(gestaltSystemVersion, &sysVersion) == noErr && sysVersion >= 0x1040) {
+	if (GetMacOSVersion() >= 0x1040) {
 		return QZ_CreateWindowQuartzSubdriver(width, height, bpp);
 	}
 
Index: src/video/cocoa/wnd_quartz.mm
===================================================================
--- src/video/cocoa/wnd_quartz.mm	(revision 11498)
+++ src/video/cocoa/wnd_quartz.mm	(working copy)
@@ -8,6 +8,7 @@
 
 #ifdef WITH_COCOA
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_4
 #include <AvailabilityMacros.h>
 
 #import <Cocoa/Cocoa.h>
@@ -784,6 +785,11 @@
 CocoaSubdriver *QZ_CreateWindowQuartzSubdriver(int width, int height, int bpp)
 {
 	WindowQuartzSubdriver *ret;
+	
+	if (GetMacOSVersion() < 0x1040) {
+		DEBUG(driver, 0, "The cocoa quartz subdriver requires Mac OS X 10.4 or later.");
+		return NULL;
+	}
 
 	if (bpp != 8 && bpp != 32) {
 		DEBUG(driver, 0, "The cocoa quartz subdriver only supports 8 and 32 bpp.");
Index: src/video/cocoa/event.mm
===================================================================
--- src/video/cocoa/event.mm	(revision 11498)
+++ src/video/cocoa/event.mm	(working copy)
@@ -8,6 +8,9 @@
 
 #ifdef WITH_COCOA
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_3
+#include <AvailabilityMacros.h>
+
 #import <Cocoa/Cocoa.h>
 #import <sys/time.h> /* gettimeofday */
 #import <sys/param.h> /* for MAXPATHLEN */
Index: src/video/cocoa/fullscreen.mm
===================================================================
--- src/video/cocoa/fullscreen.mm	(revision 11498)
+++ src/video/cocoa/fullscreen.mm	(working copy)
@@ -8,6 +8,7 @@
 
 #ifdef WITH_COCOA
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_3
 #include <AvailabilityMacros.h>
 
 #import <Cocoa/Cocoa.h>
Index: src/video/cocoa/wnd_quickdraw.mm
===================================================================
--- src/video/cocoa/wnd_quickdraw.mm	(revision 11498)
+++ src/video/cocoa/wnd_quickdraw.mm	(working copy)
@@ -8,6 +8,8 @@
 
 #ifdef WITH_COCOA
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_3
+#define MAC_OS_X_VERSION_MAX_ALLOWED     MAC_OS_X_VERSION_10_3
 #include <AvailabilityMacros.h>
 
 #import <Cocoa/Cocoa.h>
@@ -802,6 +804,10 @@
 CocoaSubdriver *QZ_CreateWindowQuickdrawSubdriver(int width, int height, int bpp)
 {
 	WindowQuickdrawSubdriver *ret;
+	
+	if (GetMacOSVersion() >= 0x1040) {
+		DEBUG(driver, 0, "The cocoa quickdraw subdriver is not recommended for Mac OS X 10.4 or later.");
+	}
 
 	if (bpp != 8 && bpp != 32) {
 		DEBUG(driver, 0, "The cocoa quickdraw subdriver only supports 8 and 32 bpp.");
Index: src/sound/cocoa_s.cpp
===================================================================
--- src/sound/cocoa_s.cpp	(revision 11498)
+++ src/sound/cocoa_s.cpp	(working copy)
@@ -8,6 +8,9 @@
 
 #ifdef WITH_COCOA
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_3
+#include <AvailabilityMacros.h>
+
 #include <AudioUnit/AudioUnit.h>
 
 /* Name conflict */
Index: src/music/qtmidi.cpp
===================================================================
--- src/music/qtmidi.cpp	(revision 11498)
+++ src/music/qtmidi.cpp	(working copy)
@@ -19,6 +19,9 @@
  */
 
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_3
+#include <AvailabilityMacros.h>
+
 /*
  * OpenTTD includes.
  */
Index: src/os/macosx/macos.h
===================================================================
--- src/os/macosx/macos.h	(revision 11498)
+++ src/os/macosx/macos.h	(working copy)
@@ -15,6 +15,8 @@
 void ShowMacAssertDialog ( const char *function, const char *file, const int line, const char *expression );
 void ShowMacErrorDialog(const char *error);
 
+long GetMacOSVersion();
+
 // Since MacOS X users will never see an assert unless they started the game from a terminal
 // we're using a custom assert(e) macro.
 #undef assert
Index: src/os/macosx/macos.mm
===================================================================
--- src/os/macosx/macos.mm	(revision 11498)
+++ src/os/macosx/macos.mm	(working copy)
@@ -1,5 +1,8 @@
 /* $Id$ */
 
+#define MAC_OS_X_VERSION_MIN_REQUIRED    MAC_OS_X_VERSION_10_3
+#include <AvailabilityMacros.h>
+
 #include <AppKit/AppKit.h>
 
 #include <mach/mach.h>
@@ -168,6 +171,20 @@
 	NSArray* languages = [defs objectForKey:@"AppleLanguages"];
 	NSString* preferredLang = [languages objectAtIndex:0];
 	/* preferredLang is either 2 or 5 characters long ("xx" or "xx_YY"). */
-	[ preferredLang getCString:retbuf maxLength:32 encoding:NSASCIIStringEncoding ];
+	if (GetMacOSVersion() < 0x1040) {
+		[ preferredLang getCString:retbuf maxLength:32 ];
+	} else {
+		[ preferredLang getCString:retbuf maxLength:32 encoding:NSASCIIStringEncoding ];
+	}
 	return retbuf;
 }
+
+
+long GetMacOSVersion()
+{
+	long sysVersion;
+
+	if (Gestalt(gestaltSystemVersion, &sysVersion) != noErr) return -1;
+	
+	 return sysVersion;
+}