MAC_OS_X_VERSION_10_6 not defined on pre-10.6

Just use a literal 1060 in header files which do not (and should not)
include MacVim.h.

src/MacVim/DBPrefsWindowController.h

@@ -43,7 +43,7 @@
 
 
 @interface DBPrefsWindowController : NSWindowController
-#if (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6)
+#if (MAC_OS_X_VERSION_MAX_ALLOWED >= 1060)
     // 10.6 has turned delegate messages into formal protocols
     <NSAnimationDelegate, NSToolbarDelegate>
 #endif

src/MacVim/MMVimController.h

@@ -8,7 +8,6 @@
  * See README.txt for an overview of the Vim source code.
  */
 
-#import <Cocoa/Cocoa.h>
 #import "MacVim.h"
 
 #ifdef MM_ENABLE_PLUGINS

src/MacVim/MMWindowController.h

@@ -8,7 +8,7 @@
  * See README.txt for an overview of the Vim source code.
  */
 
-#import <Cocoa/Cocoa.h>
+#import "MacVim.h"
 
 
 

src/MacVim/PSMTabBarControl/source/PSMTabBarControl.h

@@ -40,7 +40,7 @@ enum {
 };
 
 @interface PSMTabBarControl : NSControl
-#if (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6)
+#if (MAC_OS_X_VERSION_MAX_ALLOWED >= 1060)
     // 10.6 has turned delegate messages into formal protocols
     <NSTabViewDelegate>
 #endif