Recognize __ANDROID__ in wx/platform.h and include the appropriate headers
from wx/android.
Also fix a couple of compilation errors (in filename.cpp) and warnings (in
event.h) which only appear when building for Android.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70703 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
