changing include/g++-v3 to something a bit more obvious

[Benjamin Kosnik]

Probably the number one item on the libstdc++-v3 FAQ should be:
"I've installed libstdc++-v3.......and my header files are in include/g++-3"

This is wrong, as most people on this list know, the libstdc++-v3
header files go into include/g++-v3.

However, the difference is not really obvious to most users, and many
people knew to these libraries get easily confused from the
non-intuitive directory naming.

Since g++-3 is supposed to represent something to do with the actual
C++ ABI (I think: this has always been a bit unclear), wouldn't it
make more sense to just do something like

include/2.97

or 

include/g++-2.97

or 

include/c++-2.97

?

-benjamin