This change adds tests/ directories in the source tree to create various
subdirectories in /usr/tests/ and to install placeholder Kyuafiles for
them.
the relevant hierarchies are: cddl, etc, games, gnu and secure.
The reason for this is to simplify the addition of new test programs for
utilities or libraries under any of these directories. Doing so on a
case by case basis is unnecessary and is quite an obscure process.
mimics that of tcpdump in that for normal builds, sendmail will only be
built once. For 'make release', it is built once for the bin dist and
once for the crypto dist. This method also removes the need for two separate
Makefiles (which could become out of sync).
Suggested by: bde
Assisted by: kris
