Re: [v4l-utils v5 0/5] Add support for meson building

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

Em Wed, 16 Jun 2021 11:26:10 -0300
Ariel D'Alessandro <ariel.dalessandro@collabora.com> escreveu:

> Kieran,
> 

> >  - Meson decided to default libdir to
> >      /usr/local/lib/x86_64-linux-gnu
> >    while autoconf used
> >      /usr/local/lib
> >    (it's likely handled by the package managers anyway)  
> 
>   $ meson configure ../build-meson/ | grep libdir
>     libdir    lib/x86_64-linux-gnu    Library directory

The default isn't nice, and will likely cause troubles for the users, as 
/usr/local/lib/x86_64-linux-gnu would hardly be at the ld.so.conf list of 
paths for most people. So, when one would try to run a program, it will
fail.

> As mentioned in another response. Autotools is building with `-g -O2` by
> default, that'd the equivalent meson configuration option
> --buildtype=debugoptimized. 

I can't understand the Meson's default... no optimization and no debug!
Basically something that it is useless for both developers and for
production. I wonder why they chose a crap default like that...

> With this configuration the installtion
> sizes are not that different:
> 
>   $ du -s installation_m*
>   37068	installation_make
>   37848	installation_meson

It sounds a lot more coherent.

> In this case the difference is related to libtool `.la` files not being
> generated by meson and gconv/ only installed by meson. The latest is
> probably a feature being only detected by meson in this case, will check
> that out.

It was opted to not enable gconv by default, as similar patchset - needed
to support ARIB STD B-24 charset used by Japanese digital TV - was sent to 
gconv upstream (not sure if it was merged or not). On other words, the 
contrib/gconv stuff is independent of v4l-utils itself: it basically
adds an extra charset to be used by gconv upstream.

The only reason why it is present at v4l2-utils is that this charset
is present on ISDB tables on TV broadcasts in Japan. The gconv library
needs to support it, in order to  convert characters from MPEG tables
to the system's charset.

Btw, that's basically one of the reasons why we print a summary of the
options when ./configure runs.

Thanks,
Mauro