[v3] abi docs, testsuite

[Benjamin Kosnik]

>2004-05-13  Jonathan Wakely  <redi@gcc.gnu.org>
>
>        * docs/html/abi.html: Document effect of -fabi-version on value
>        of __GXX_ABI_VERSION, and that it's defined in c-cppbuiltin.c.
>        Fix markup.

Looks great, thanks for the fixups!

-benjamin