NFD

This wouldn't work. Most heavy processing is inside core/logger.hpp and I see no way how this file can be customized without macros. We can add --with-logger option, but this should enable specific conditional compilation. In ns-3 case, logger-factory.hpp|cpp will become empty with trivial implementation of logger.hpp, in case of android, I'm expecting logger-factory stay the same and logger.hpp have slightly different defines.

Can wscript somehow make #include "core/logger.hpp" (or change to #include "logger.hpp" if necessary) refer to a different file when --with-logger is present?

If the file is present in "core/" folder, it may get tricky and platform-dependent. In boost libraries, such cases are handled with defines (e.g., the way kqueue is enabled on OSX and epoll on linux as io_service backend).

Can we use something like:

#if ANDROID
#include "nfd-android/core/logger.hpp"
#elif NS3
#include "ndnsim/core/logger.hpp"
#else

// regular logger

#endif

Then tweak wscript so that logger.cpp isn't compiled when not needed.

My point is: don't put Android or ns-3 code in NFD, but include them from outside.

Hmm.. I have a mixed feeling about this, but here is a slightly more universal approach:

#if defined(HAVE_CUSTOM_LOGGER)
#include "custom-logger.hpp"
#else

... regular logger


#endif // defined(HAVE_CUSTOM_LOGGER)

This way we don't need targeted specializations, which can in both android and ndnSIM cases be done in the same way.