The last update mistakenly removed wafHook and the patch required to make cross-
compilation work. In addition, the bundled version of heimdal is now too new to
work with asn1_compile from the heimdal package in nixpkgs (it isn't out of
date, there just hasn't been a release in years and samba uses an unreleased
version).
To fix the latter issue, the native build of samba saves asn1_compile and
compile_et from the bundled heimdal into the dev output, allowing them to be
available at build time when cross-compiling.
