Replace legacy make with bmake

Replace legacy make with bmake

The proper way to detect which make is building the makefile is to check
for .PARSEDIR.  If present, bmake is processing the makefile.  For the
time being, both make will be supported for bootstrapping purposes, but
in time the check can be removed, say for the DragonFly 3.6 release.

The abundance of .ORDER commands in bsd.dep.mk caused a breakage when
building world in parallel with bmake.  Likely some order constraints
were impossible to achieve, and bmake just stopped while legacy did the
best it could.  In any case, the majority of the .ORDER commands were
replaced by a single .ORDER command which solved the problem.

The legacy make is disconnected in this commit set, but the source files
will be removed soon.