and into their own directories. Also do some cleanups with build/_build
and pkginstall -- we get rid of _build and simply run pkginstall as
part of the "build" target.
Introduce a new mechanism to handle varying directory depths under
${WRKSRC} in which we find files to override, e.g. configure, config.*,
libtool, etc. OVERRIDE_DIRDEPTH is a package-settable variable that
specifies how far under ${WRKSRC} the various targets should look,
and it defaults to "2". We preserve the
meaning of the various *_OVERRIDE variables, so if they are defined,
then their values supersede the OVERRIDE_DIRDEPTH mechanism.
devel/tla will need to specially set OVERRIDE_DIRDEPTH to 3 (see log
for revision 1.1857 for bsd.pkg.mk -- to be done in a separate commit.
