determined, since BSDSRCDIR's default of /usr/src might not exist and the
calculation of _SRC_TOP_OBJ_ would then generate a warning :-(.
_SRC_TOP_ can now == "" if make(1) (or a parent make(1)) was started
outside of the NetBSD source tree.
Now, if _SRC_TOP_ != "", BSDSRCDIR defaults to ${_SRC_TOP_} and
BSDOBJDIR defaults to the objdir of ${BSDSRCDIR}.
Failsafe defaults for BSDSRCDIR (/usr/src) and BSDOBJDIR (/usr/obj)
are provided later in the file.
This should result in a usable BSDSRCDIR default (i.e, _SRC_TOP_ if
running from within the source tree), with safe fallbacks as appropriate
(/usr/src, as always), meaning that BSDSRCDIR should be able to be used
instead of _SRC_TOP_ in the source tree, although I need to carefully
test this. *aaaiiiieeee!!!*. (Now I understand some of Todd's pain :)
46569c985e