$(.CURDIR}/obj search while retaining compatability of new
prefix with cwd for the current source tree builds.
.TARGETOBJDIR has been removed from make and CANONICALOBJDIR set in
bsd.obj.mk
The builtin object directory searching is defined specifically as:
If MAKEOBJDIRPREFIX is defined, the search order is
${MAKEOBJDIRPREFIX}${.CURDIR}
${.CURDIR}
Else if MAKEOBJDIR is defined, the search order is
${MAKEOBJDIR}
${.CURDIR}
Otherwise, default to the search order
${.CURDIR}/obj.`uname -m`
$(.CURDIR}/obj
/usr/obj${.CURDIR}
${.CURDIR}
Reviewed by: bde
18e24ede6b