Remove unused code in cocoa file dialog implementation.

The removed function was used for OS X versions prior to 10.7 and was not used any more.

src/osx/cocoa/filedlg.mm

@@ -52,32 +52,6 @@
 // then the delegate method - (BOOL)panel:(id)sender shouldShowFilename:(NSString *)filename will have to
 // be implemented
 
-namespace
-{
-
-bool HasAppKit_10_6()
-{
-    // Even if we require 10.6, we might be loaded by an application that
-    // was linked against 10.5.  setAllowedFileTypes will still be ignored
-    // in this case.  From NSSavePanel.h:
-    // NSOpenPanel: On versions less than 10.6, this property is ignored.
-    // For applications that link against 10.6 and higher, this property will
-    // determine which files should be enabled in the open panel.
-    int32_t version = NSVersionOfLinkTimeLibrary("AppKit");
-    if (version == -1)
-    {
-        // If we're loaded by an application that doesn't link against AppKit,
-        // use the runtime version instead.  This check will not work for the
-        // case above.
-        version = NSVersionOfRunTimeLibrary("AppKit");
-    }
-
-    // Notice that this still works correctly even if version is -1.
-    return version >= 0x40e2400 /* version of 10.6 AppKit */;
-}
-
-} // anonymous namespace
-
 @interface wxOpenPanelDelegate : NSObject wxOSX_10_6_AND_LATER(<NSOpenSavePanelDelegate>)
 {
     wxFileDialog* _dialog;