Fwd: Re: Why is building a cross compiler "out-of-the-box" always broken?

[Segher Boessenkool <segher at kernel dot crashing dot org>]

(Stephen typoed the gcc address, forwarding)


From: Segher Boessenkool <segher@kernel.crashing.org>
Date: 21 augustus 2007 17:10:30 GMT+02:00
To: "Stephen M. Kenton" <skenton@ou.edu>
Cc: gcc@gcc.cnu.org
Subject: Re: Why is building a cross compiler "out-of-the-box" always  
broken?


> I got 17 "minimal" compilers to build using your help. Upon closer 
> examination I realized that you are not building glibc, which of 
> course if fine for your application testing kernel builds.

Half of my targets do not even support glibc :-)

> When I tried to use those compilers to configure glibc, it complained 
> about needing unwind support.  Presumably because of 
> --enable-sjlj-exceptions.

Most likely yes.

> I modified the gcc configure to allow --with-headers to point to the 
> kernel headers and still set inhibit libc,

What sets the inhibit_libc -- do you modify configure itself for that,
or does some configure option do it?

>  then I removed the --enable-sjlj-exceptions and it built about the 
> same set of compilers as before.  Glibc configure died for another 
> reason after that, but that's a different issue.
>
> I really think that lumping kernel and libc headers together in the 
> configure when deciding whether to set inhibit_libc is a mistake. It 
> looks one should be independent of the other.

Another problem is that GCC should provide some of those headers itself
really; certainly the headers for the parts of C that it does implement
itself.  That's a long-standing issue though, is there any progress on
it (or even a plan for fixing it)?


Segher