The ctags implementation from Universal Ctags (https://ctags.io/)
is hopefully the best ctags alternative that works with e.g. vim.
Remove the ctags binary from emacs so it does not conflict with
this new package (the etags program remains for emacs to use).
This fixes breakage for gnulib-using packages which otherwise
defines AT_EACCESS, which does not work on Android 6.
Bump build revisions for coreutils and emacs to rebuild them
with this patch.
