[v3] don't precompile extc++.h

[Benjamin Kosnik]

Precompiling extc++.h, ie all of libstdc++'s extensions, causes an ICE
on some primary platforms.

See:
http://gcc.gnu.org/PR28217

Mike Stump has hidden a patch in some followup email. Hopefully he'll
repost in a less disguised format.

In the meantime, this removes the problematic PCH from the compilation
process.

tested x86/linux

-benjamin

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: p.20060712-1
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20060712/c20f1c5b/attachment.ksh>