[RFC, patch] Detect lack of 32-bit devel environment on x86_64-linux targets

[Richard Biener]

On Fri, Jan 31, 2014 at 3:33 PM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Fri, Dec 13, 2013 at 10:47 PM, FX <fxcoudert@gmail.com> wrote:
>>> The patch is okay, but if other architecture maintainers could add
>>> similar checks for their ports (SPARC and PPC, I guess), it would be nice.
>>
>> Thanks, committed as rev. 205975
>>
>> Adding other systems to the list of checks will be easy, once the maintainers confirm that they want to opt in into it.
>
> In our default build environment for package building GCC no longer builds
> because of this:
>
> [  152s] /usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/bin/
> ld: skipping incompatible /usr/lib64/gcc/x86_64-suse-linux/4.8/libgcc.a when sea
> rching for -lgcc
> [  152s] /usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/bin/
> ld: cannot find -lgcc
> [  152s] /usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/bin/ld:
> skipping incompatible /usr/lib64/gcc/x86_64-suse-linux/4.8/libgcc_s.so
> when searching for -lgcc_s
> [  152s] /usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/bin/ld:
> cannot find -lgcc_s
> [  152s] collect2: error: ld returned 1 exit status
> [  152s] configure: error: I suspect your system does not have 32-bit
> developement libraries (libc and headers). If you have them, rerun
> configure with --enable-multilib. If you do not have them, and want to
> build a 64-bit-only compiler, rerun configure with --disable-multilib.
>
> the issue is that while we do have 32bit glibc support installed but not all
> required files for the host compiler to produce 32bit executables - which
> isn't needed - the compiler we bootstrap will have all the support for this.
>
> In fact, a x86_64 multilib GCC can be just bootstrapped fine with a
> non-multilib x86_64 compiler which you also disallow with the above check.
>
> I don't see how you can do this configure check in its current form early,
> before you've built the stage1 compiler.
>
> So - please consider reverting this patch or at least provide a way to
> override the check.

I've just seen that an explicit --enable-multilib is a way to do that.

Still I think this is odd behavior - as you are matching x86_64-*linux
you can as well check for /usr/include/gnu/stub{,-64}.h.  I don't know
of any distribution where you can have the header package installed
without the corresponding libraries.

Richard.

> Thanks,
> Richard.
>
>
>
>> FX