Log Message:
o Added description for patches/patch-aa
o Removed the do-install, and avoid the tmux's rough install(1) too.
Simply export our INSTALL_*
o Removed DEBUG_FLAGS (why we need it? and if we need it isn't better and
simpler to use a "debug" option and then define DEBUG?)
o Marked as DESTDIR ready
o Last, but not least, make pkglint(1) happier!

These changes and especially the last Fulvio commit (build issues about
strtonum(3) and vis(3)) need PKGREVISION++, so bump PKGREVISION.