While all of elfutils does not build with clang, the libelf part does
and is needed by ltrace. So keep libelf as a package and let it replace
elfutils for now.
This fixes Android 6 problems (so closes#26).
It also rebuilds termux-elf-cleaner when needed
and bumps some build revisions for packages
needed updates to remove DT_VERDEF and DT_VERDEFNUM.
Fredrik Fornwall