planned bugfix release of base

[Richard Frith-Macdonald]

I'd like to do a bugfix release of base (1.20.1) from the stable branch this 
coming weekend.

This would be essentially the same as svn trunk (I guess I'd make an unstable 
bugfix release of 1.21.1 too), consisting of all the bugfixes and optimisations 
since 1.20.0 along with new timezone data, improvements to timezone detection, 
and a change to install gdomap without the setuid bit set by default, and a 
configure change to require the compiler to support using the NSConstantString 
class from base rather than NXConstantString from the runtime (unless 
explicitly configured otherwise).

It would be nice if people could check this out in case any problem has been 
introduced (I hope not).