Let me add that I just discovered that I have

/usr/local/lib/libwx_macud-2.5.3.dylib

but not the version 2.6.0 that is being sought in the make.

I did find:

/Users/gpetty/wx/v263/build-unicode-debug/lib/libwx_macud-2.6.0.dylib

I assume the build should be looking for that one; I don't know why it isn't.