Build instructions

[Jose E. Marchesi]

> Good day everyone,
>
> Yesterday, following Piero's advice, I cloned the source tree from GCC
> rather than the forge and then ran a build (first time with non-forge
> build).
>
> A few observations:
>
> - the build instructions at https://gcc.gnu.org/wiki/Algol68FrontEnd relate
>   to working with the forge version; I see there is a similar set in
>   gcc/gcc/algol68/README (once you have the source tree in place)
>   but it lacks steps for building docs, running tests; could we offer a
>   more full example on the wiki for using with the GCC source tree,
>   including the URL for git clone?

I just updated the instructions in the wiki to refer to the main GCC
tree, and to the right README file.

> - I seem to recall comments about using a parallel make process; is that
>   a good idea?

Very good idea to use -j when building GCC. Otherwise it might take a
loong time.

> - ../configure suggested another flag for me as I don't have i386 stuff
>   installed on my machine, which was handy and maybe should be
>   mentioned in the instructions.


You mean --disable-multilib?

> - maybe it was because I wasn't building with i386 but my build ran
>   in much less time than my first build from the forge source tree.  I
>   found this surprising, but no error messages hinting as to why.
>
> I would be happy to write a first draft to address what I mentioned above,
> if anyone is interested, instead of just asking others to do it for me.
> Please let me know!