This means moving include of local.sys.mk and src.sys.mk too.
Introduce new includes to take the early slot, for the purpose
of being able to influence toolchains and the like.
Differential Revision: D2860
Reviewed by: imp
Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.
Still need to add real targets under targets/ to build packages.
Differential Revision: D2796
Reviewed by: brooks imp
replace it with the absolute path of .PARSEDIR, so that sub-makes
launched from objdirs (eg kernel) can still find the correct mk files.
Reviewed by: obrien
src/sys and the rest of the tree for builds.
o eliminate including bsd.mkopts.mk for the moment in kern.opts.mk
o No need to include src.opts.mk at all anymore. The reasons for it
are now coverted in sys.mk and src.sys.mk.
