precompiled headers can cause big slowdowns

[Neil Booth]

Robert Lipe wrote:-

> It took 97 minutes with the Darwin compiler and cpp-precomp was the
> consumer of clock cycles.

That sounds like something silly in cpp-precomp and could probably be
fixed.  Besides, what these issues really show is that there is a need
to be able to select whether or not to precompile; not that
precompiling is necessarily bad.

Neil.