darwin may lose primary target status on FSF gcc

[Jack Howarth]

Oh, I should clarify how I measure the first stable release.
Until about gcc 4.2, gfortran was in an unstable development
mode that exempted it from the normal commit rules (ie when
the gcc release was branched only commits for regression fixes
and bugs were allowed). It was in such a primordial state up
to gcc 4.2.0 that those rules were waived and the gfortran developers
were free to commit to the gfortran section of the compiler
at any time. After it was deemed stable in 2007, the gfortran
compiler fell under the normal rules for developing in gcc.
               Jack