Unicode compilation fix

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@42784 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/x11/utils.cpp

@@ -272,8 +272,11 @@ void wxCloseDisplay()
 
 bool wxSetDisplay(const wxString& displayName)
 {
-    Display *
+    Display *dpy = XOpenDisplay
-        dpy = XOpenDisplay(displayName.empty() ? NULL : displayName.mb_str());
+                   (
+                    displayName.empty() ? NULL
+                                        : (const char *)displayName.mb_str()
+                   );
 
     if ( !dpy )
     {