clarification requested in egcs installation

[Martin von Loewis]

> On http://egcs.cygnus.com/install/configure.html , you describe the
> --with-local-prefix and --with-gxx-include-dir options, saying that their
> use is normally not needed.  Unfortunately, the description is not quite
> clear, at least to me.

Even worse, it appears to be incorrect.

> Do these options say that egcs should install its headers in the named
> directories instad of the normal places, or do they say that egcs should
> look there for the g++ header files during installation?

These are directories searched in addition to the normal places.
local_prefix gives an additional directory to /usr/include (searched
before /usr/include), and gxx-include-dir gives an additional directory
search for C++ compilation (before local_prefix).

> For example, on my machine, g++ is installed in /usr/gnu instead of
> /usr/local.  Does that mean that when I install egcs, I should say
> --with-gxx-include-dir=/usr/gnu/include ?  What about --with-local-prefix ?

You don't need to change --with-gxx-include-dir; it defaults to a
directory relative to ${prefix}, not to /usr/local/include/g++; this
is also the place where those header files get installed. 

If you have header files in /usr/gnu/include you want to be found by
default, you give --with-local-prefix=/usr/gnu/include. If you don't
need that feature at all, you can say --with-local-prefix=no.

Regards,
Martin