Fallout (mostly runtime library-related) from GCC version number change (take two)

[Paolo Carlini]

Hi again Zack,

> ...........
>
>Please try the
>appended patch on top of the patch I already provided; I will be
>re-testing overnight, myself (your daytime, sorry).
>  
>
Now the build completes fine but the install problem is *not* fixed: 
everything ends up inside /usr/local/gcc-exp/include/c++/ instead of the 
correct /usr/local/gcc-exp/include/c++/4.1.0/, exactly as you told me 
yesterday, in other terms.

Considering, for instance, the debug subdir, this is used at install time:

    /usr/local/gcc-exp/include/c++//./debug

Paolo.