Problems with building gcc 4.2.1

[Tim Prince]

Simon King wrote:
> Dear Tim, dear gcc team,
> 
> Recall that when building gcc 4.2.1, i got this error:
> In file included from /usr/include/features.h:346,
>                  from /usr/include/stdio.h:28,
>                  from /usr/local/gcc-4.2.1/gcc/tsystem.h:90,
>                  from /usr/local/gcc-4.2.1/gcc/crtstuff.c:68:
> /usr/include/gnu/stubs.h:7:27: error: gnu/stubs-32.h: Datei oder
> Verzeichnis nicht gefunden
> 

> From the behaviour of stubs.h, we see that __WORDSIZE actually is 32 
> (which is wrong). Hence, apparently __x86_64__ was not defined.
> 
> Now, i work on x86_64. Why isn't __x86_64__ defined, and where should it 
> usually be defined?

This define should be set by your bootstrap compiler.  On a 64-bit OS,
gcc should use -m64 and set the x86-64 options by default. If you are
trying to build 64-bit gcc on a 32-bit OS installation, you will need to
follow the cross-compiler build instructions, but you would still
require a 64-bit OS to make use of the newly built compiler.