Is there a particular reason this uses share/lynx rather than the standard share/examples/lynx for the sample config files?
You should be able to use "INSTALL_TARGET= install install-help install-doc" rather than post-install. There's a "--sysconfdir doesn't work?" comment, it's not in the Makefile, what were you trying to do with it? You can't just add that to CONFIGURE_ARGS because ports overrides it, you can set SYSCONFDIR instead to point it elsewhere though, but it looks like you're just trying to override the install location for fake and in that case the FAKE_FLAGS ought to be enough ..
