Fix wxMotif build after recent argv changes

Update wxMotif too after 70a499f635.

src/motif/app.cpp

@@ -206,11 +206,8 @@ bool wxApp::Initialize(int& argc_, wxChar **argv_)
             }
         }
 
-        argc = argcX11;
-
         // update internal arg[cv] as X11 may have removed processed options:
-        argc = argc_;
-        argv = argv_;
+        argv.Init(argcX11, argvX11);
     }
     //else: XtOpenDisplay() didn't modify our parameters