Problems with 2.90.8

[Benjamin Kosnik]

> switch. Can it be automagically made default then gcc is rebuilt with
> new libstdc++ ?

Yes. If you use CVS gcc, and have "libstdc++-v3" as the library source 
dir, and then  pass in

--enable-libstdcxx-v3

at configure time, then the compiler built with use libstdc++-v3 and have 
namespaces enabled by default. 

Post 2.90.8, this is going to be the recommended way to install, and the 
makefiles and mkcheck.in, etc. have been modified to support this.

-benjamin