This should hopefully fix current issues with bootstrap buildworlds from

This should hopefully fix current issues with bootstrap buildworlds from
4.x and older versions of DFly, and with user-specified CCVER and CPUTYPE
environment variables.

Explicitly override CCVER in buildworld in a backwards compatible fashion
when building gcc2's and gcc3's startup libraries.  Also override CCVER
in gnu/lib/gcc{2,3}/Makefile when bootstrapping from older DFly or FBsd
systems which do not implement the '.makeenv' make directive.

In bsd.init.mk detect when CCVER is changed by a Makefile or Makefile.inc and
rerun bsd.cpu.mk to update the _CPUCFLAGS set, which is assigned in bsd.cpu.mk.
We relay on the fact that ${} variables are not resolved until rules accessing
them are actually run.

Clean up objformat (no operational changes).