[Bug web/107651] Having two different kind of indexes is very useful still

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107651

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
For the install page, one index should be index of configure option and another
one will be of the env variables.

For the preprocessor has an index of env variables too.

Maybe even in the main document you have a list of env variables because of
ASAN options. Or that should be part of the library section; I don't know
fully.