krb5: remove libedit from the bootstrap tools

libedit breaks the bootstrap on MacOS and Linux.

Activate libedit only for the regular build not for the bootstrap
tools

While here fix the definition of the dependency chain between
libkrb5ss and libedit (and libtinfow) via src.libnames.mk

Remove a local patch to find the readline compatible header and
find them via proper CFLAGS.