This update is reported to be self hosting with -O2.
This update contains a hack of setting REQUIRES_RTTI=1 globaly which
isn't optimal, but works around a problem a people have seen in
testing.
Feature safe: yes
Add printf0 support. [1]
Install the clang C headers (excluding std*.h since we have our own) now
that the installer puts them somewhere sane.
Submitted by: ed