[Mesa-dev] [PATCH] docs/autoconf: mention CC/CXX when doing multilib builds

[Emil Velikov]

On 13/08/14 22:22, Ilia Mirkin wrote:
> On Wed, Aug 13, 2014 at 5:16 PM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
>> Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
>> ---
>>
>> Unless someone object I would like to squash this patch with the
>> previous one.
>>
>> -Emil
>>
>>  docs/autoconf.html | 16 ++++++++++++++--
>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/docs/autoconf.html b/docs/autoconf.html
>> index f27838f..c225659 100644
>> --- a/docs/autoconf.html
>> +++ b/docs/autoconf.html
>> @@ -141,14 +141,26 @@ assembly will not be used.</p>
>>  <dt><code>--host=</code></dt>
>>  <dd><p>By default, the build will compile code for the architecture that
>>  it's running on. In order to build Mesa on a x64-86 machine that is to run
> 
> While you're fixing stuff, x86-64
> 
Ack, will do.

>> -on a i686, one would need to set the options to:
>> +on a i686, one would need to set the options to:</p>
>>
>>  <p><code>--build=i686-pc-linux-gnu --host=i686-pc-linux-gnu</code></p>
>>
>>  Note that these can vary from distribution to distribution. For more
>>  information check with the
>>  <a href="https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Specifying-Target-Triplets.html">
>> -autoconf manual</a>.</p>
>> +autoconf manual</a>.
>> +
>> +
>> +<p>In some cases a single compiler is capable of handling both architectures
>> +in that case one would need to set the <code>CC,CXX</code> variables
>> +appending the correct machine options. Seek your compiler documentation for
>> +further information -
>> +<a href="https://gcc.gnu.org/onlinedocs/gcc/Submodel-Options.html"> gcc
>> +machine dependent options</a></p>
>> +
>> +<p>The following is the complete setup needed to compile on my Archlinux setup</p>
> 
> There's nothing about the below that's specific to Arch, or any
> distro, really -- I'd avoid the explicit distro reference.
Haven't touched any other distro but Arch in years. Yet it makes sense to drop
the distro reference but keep the example.

> Do you
> actually need the --build and --host things? I thought that was if you
> were going to use a cross-compiler. I only have
> x86_64-pc-linux-gnu-gcc, no i686-...-gnu-gcc.
> 
--build/host (at lest) used to be required by mesa, as some bits were built
differently when doing cross-compilation. Not sure what the case is now - I
care not look in src/{glsl,mesa} which is where all of that chaos was.


> In the past I've just done CFLAGS=-m32 CXXFLAGS=-m32 and it has worked
> like a charm. But perhaps there's a downside to doing that...
> 
I cannot think of any side effects to be honest (barring any bugs in mesa).
Yet I would love if people avoid touching any *FLAGS :)

Thanks
-Emil

>> +
>> +<code>./configure CC="gcc -m32" CXX="g++ -m32" --build=i686-unknown-linux-gnu --host=i686-unknown-linux-gnu ...</code>
>>  </dd>
>>  </dl>
>>
>> --
>> 2.0.2
>>
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