Precompiled headers (or other speed ups)

[dewar@gnat.com]

<<was posted in last August, but there is a good example of how the parser
can dominate just about everything.  That message kicked off a very good
discussion on precompiled headers and parsing performance in C++.
>.

This is quite surprising, depending on what parsing means, if parsing
means just building a syntax tree from the grammar, it is amazing that
this should take any time at all compared to other phases.