rewrite sed logic used in Makefiles and move into dosubst awk script.

rewrite sed logic used in Makefiles and move into dosubst awk script.

include 'bin' and its files in dist files, this is where dosubst is located.

While the invocation (passing of the variables)
is not optimal (yet, will be changed), this
will in the end allow sharing code between Makefiles better,
and maybe drop sed usage in the future.