locking types for WRKDIR and LOCALBASE.
The default values are currently based on PKGSRC_LOCKTYPE, but the
recommended values are different. For LOCALBASE, the recommended value
is "sleep", since after one transaction has finished, the next can be
done in the new LOCALBASE without problems.
The situation is different though in WRKDIR. After one transaction has
finished there, it is often the case that the directory is removed,
including the lockfile. In that case, the package has usually been
installed and packaged successfully, and it would be a bad idea to let
the next transaction try to do the same again. Therefore, the
recommended value here is "once".
Added two targets acquire-localbase-lock and release-localbase-lock,
which mark the complete LOCALBASE directory as locked, so that multiple
packages cannot run the install, deinstall or bin-install targets at the
same time.
The install target aquires locks in both WRKSRC and LOCALBASE, the other
two targets only need the LOCALBASE lock, since they may be run without
WRKSRC being present on the system.
locking.mk must be included before tools.mk and the PKG_FAIL_REASON
check.
