Compilation fix for PCH-less compilation.

To use wxTheApp (added in r62337) we need to include wx/app.h.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62352 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/stdpaths.cpp

@@ -29,6 +29,7 @@
 #include "wx/stdpaths.h"
 
 #ifndef WX_PRECOMP
+    #include "wx/app.h"
     #include "wx/wxcrt.h"
     #include "wx/utils.h"
 #endif //WX_PRECOMP