Assume sizeof(wchar_t) is always 4 under OS X.

wchar_t used to be 2 bytes in Mach-O builds but they're not supported any
longer so remove the code checking for sizeof(wchar_t) and just assume it's
always 4.

Closes #10442.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66028 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/carbon/nonownedwnd.cpp

@@ -323,17 +323,13 @@ static pascal OSStatus KeyboardEventHandler( EventHandlerCallRef handler , Event
         GetEventParameter( event, kEventParamKeyUnicodes, typeUnicodeText, NULL, dataSize , NULL , charBuf ) ;
         charBuf[ numChars - 1 ] = 0;
 
-#if SIZEOF_WCHAR_T == 2
-        uniChar = charBuf[0] ;
-#else
         wxMBConvUTF16 converter ;
         converter.MB2WC( uniChar , (const char*)charBuf , 2 ) ;
-#endif
 
         if ( numChars * 2 > 4 )
             delete[] charBuf ;
     }
-#endif
+#endif // wxUSE_UNICODE
 
     GetEventParameter( event, kEventParamKeyMacCharCodes, typeChar, NULL, sizeof(char), NULL, &charCode );
     GetEventParameter( event, kEventParamKeyCode, typeUInt32, NULL, sizeof(UInt32), NULL, &keyCode );