an interesting idea, but...

[Zack Weinberg <zack@rabi.columbia.edu>]

Durning a build, cpp is invoked (number of active suffixes)+1 times
for each source file in the library.  Profiling suggests there would
be upwards of 25% improvement in build time from invoking it only
once.  This is easy to put into the makefiles, but there's a problem:
a lot of code cares about whether it's going into the static, shared,
or profiled library.  It finds out with #ifdefs.  If I run cpp once,
all this code is miscompiled.

Any thoughts on how to work around the problem?

zw