compilation fix for ASCII STL build (#9661)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@54424 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/control.cpp

@@ -173,7 +173,7 @@ bool wxControl::MSWCreateControl(const wxChar *classname,
     // Notice that 0xffff is not a valid Unicode character so the problem
     // doesn't arise in Unicode build.
     if ( !label.empty() && label[0] == -1 )
-        ::SetWindowText(GetHwnd(), label);
+        ::SetWindowText(GetHwnd(), label.c_str());
 #endif // !wxUSE_UNICODE
 
     // install wxWidgets window proc for this window