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Date: Fri, 10 Apr 2015 10:06:44 -0400
From: John Snow <jsnow@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] configure: improve multiarch support for
 pkgconfig
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To: Peter Maydell <peter.maydell@linaro.org>, Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, QEMU Developers <qemu-devel@nongnu.org>



On 04/10/2015 08:55 AM, Peter Maydell wrote:
> On 10 April 2015 at 13:21, Stefan Hajnoczi <stefanha@redhat.com> wrote:
>> On Thu, Apr 09, 2015 at 05:36:12PM -0400, John Snow wrote:
>>> This will improve the multi-arch compilation for hosts using gcc.
>>> configurations using clang won't see an improvement, but also won't
>>> see a regression.
>>
>> The commit description does not explain what this patch "improves".
>> Please add this explanation (or something equivalent) when merging:
>>
>> 32-bit compilation on 64-bit hosts is broken because pkgconfig isn't
>> multi-arch aware and selects the 64-bit glibconfig.h header file.  That
>> file assumes the LP64 data model so guint64 is defined as unsigned long.
>> This does not work for 32-bit builds where sizeof(unsigned long) == 4
>> bytes.
>
> Is this actually a fix for multiarch (which is the Debian/Ubuntu
> approach where everything is split into /lib/i386-linux-gnu and
> /lib/x86_64-linux-gnu and so on) or for the RedHat setup with /lib
> and /lib64? (I forget the name of the latter, maybe multilib?)
>
> -- PMM
>

It should apply to both, AFAIK. (Testing welcome ...!)

I wasn't very confident with the fix (I've been sitting on it for a 
while ...), but there's some good feedback, so I'll respin.

Thanks everyone.

--js