Re: Regressions in build process introduced since August

[Paolo Bonzini <pbonzini@redhat.com>]

On 23/11/20 16:41, Daniel P. Berrangé wrote:
> On Mon, Nov 23, 2020 at 03:28:39PM +0000, Daniel P. Berrangé wrote:
>> On Mon, Nov 23, 2020 at 03:40:48PM +0100, Stefan Weil wrote:
>>> Am 23.11.20 um 14:55 schrieb Paolo Bonzini:
>>>
>>>> On 21/11/20 12:09, Stefan Weil wrote:
>>>>> --- a/meson.build
>>>>> +++ b/meson.build
>>>>> @@ -649,9 +649,8 @@ if get_option('vnc').enabled()
>>>>>      vnc = declare_dependency() # dummy dependency
>>>>>      png = dependency('libpng', required: get_option('vnc_png'),
>>>>>                       method: 'pkg-config', static: enable_static)
>>>>> -  jpeg = cc.find_library('jpeg', has_headers: ['jpeglib.h'],
>>>>> -                         required: get_option('vnc_jpeg'),
>>>>> -                         static: enable_static)
>>>>
>>>> Does it work if you just remove "static: enable_static"?  That asks
>>>> Meson to look explicitly for a ".a" file instead of just adding a
>>>> "-ljpeg" flag.  However it is not what configure used to do so it
>>>> shouldn't be necessary.
>>>
>>>
>>> No, that does not help. Neither header file nor library will be found in my
>>> cross environment without using the provided --extra-cflags and
>>> --extra-ldflags, because all those files are installed below
>>> /usr/i686-w64-mingw32/sys-root/mingw or
>>> /usr/x86_64-w64-mingw32/sys-root/mingw which is not searched by the default
>>> compiler settings. The Meson checks obviously don't use those flags.
>>>
>>> pkg-config provides the right paths and works therefore.
>>
>> Relying on pkg-config should be our strong preference. I expect we're doing
>> the old fashioned library check just for historical reasons, but even RHEL-7
>> supports pkg-config for libjpeg. So I think we're safe to just unconditionally
>> rely on pkg-config these days and thus have it "just work" for cross compiles
>> too.
> 
> For that matter I think we can also rely on  pkg-config for sasl too, as
> again all our supported platforms have a new enough cyrus-sasl to have
> a pkg-config file present these days.

Yes, I agree.  However we have at least -lmpathpersist that does not 
have a pkg-config file.  In the meanwhile I'll integrate Stefan's patch. 
  Stefan, is libjpeg the only one that is affected in your build 
environment?

Paolo