I consider POSIX more important than BSD, because it's something where I
can refer to something other than the system as a guideline to how to
expect the system to behave, and because it gives me a reference for
compatability with other systems.  It's bad enough that I can't do quite
everything I want in strictly conforming Standard C.  I *much* prefer
writing within a standard.

If I have to include code to work around or deal with anything which
is not standard, I have additional work which I consider gratuitous.

I don't mind extensions, but I mind deviations.

-s