I don't understand the "gcc" and "gcc3" compiler modules

[Gb]

On Fri, 11 Jan 2008, Gb wrote:

> Moreover, what is the reason behind having a "GCC3_PREFIX" variable
> in the BUILD script of the "qemu" module to select "gcc3" specifically,
> if it can be either "the sole compiler" or "not installed"?
>
> And how can be the "qemu" module useful if I want to keep "gcc" (4.2.2)
> as the installed compiler?
>
> I am probably confused.

On #lunar, I learned that technically only one gcc compiler version
can be the DEFAULT one in lunar at a time.
But it seems to be possible to  have more
than one compiler version installed at the same time.

The point is that the DEFAULT/"gcc"-named(?)  one is /usr/bin/gcc,
while the others get installed as /opt/lunar/gcc* (if I am not wrong).

Unfortunately, in my system I always fail to get anything installed in /opt/lunar/gcc*.
This is also the reason why I get an error in the BUILD phase of qemu:
there is no gcc3 in /opt/lunar.

What steps are used to install more than on compiler, usually?
I guess:

1. lin -cr gcc (should be avoided, it should be there already)
2. lin -cr gcc3 (??) (this fails on my system to put anything in /opt/lunar)

Please let me know.

Gb