* Rewrite src/tools Make logic to work like the rest of the tree wrt
"dependall" and "install". The old "make build" hack is gone.
* Remove the MKTOOLS logic. This was linked to the "make build" hack,
and was only needed because TOOLDIR originally had no writable default.
* Redo the GNU configure/make logic to make it fit reasonably in a
BSD make wrapper. Use new ${.ALLTARGETS} variable to scan for
targets in $(srcdir), and mark them with .MADE: to prevent rebuilding.
* Only build cross tools in src/tools; remove some messy logic in
src/usr.* and src/gnu/usr.* that would do target filename rewriting
(improves consistency and readability).
* Add the ability to build cross gdb at tool build time by setting
MKCROSSGDB (default no) to "yes" in mk.conf.
* Add src/tools/groff and set up paths to work with this cross groff.
defined, as <bsd.own.mk> always sets it; also, compare only against "yes"
(not "no") for a yes/no check, as there are two negative states ("no" and
"never").
the USETOOLS=no and !defined(USETOOLS) cases, is not guaranteed to exist.
However, the current functionality overrides any potentially correct
hand-set definition of COMPILE_ET, causing build breakage.
Now the line setting COMPILE_ET only happens if COMPILE_ET is not already
set, like so:
.if !defined(COMPILE_ET)
COMPILE_ET= ${COMPILEETOBJ}/compile_et
.endif
