- Fix some style errors I made back in 1995.
- Add a new flavor of the err(3) family, which takes an explicit
errno argument rather than implicitly examining errno. This
will make it easier to use these functions in conjunction with
modern library interfaces that return an errno value explicitly.
for gcc >= 2.5 and no-ops for gcc >= 2.6. Converted to use __dead2
or __pure2 where it wasn't already done, except in math.h where use
of __pure was mostly wrong.