Re: [PATCH v1 1/1] Add support for meson building

[Ariel D'Alessandro <ariel@vanguardiasur.com.ar>]

Hi Gregor,

Thanks for the report.

On 6/22/20 4:09 PM, Gregor Jasny wrote:
> Hello,
> 
> On 6/22/20 8:07 PM, Gregor Jasny wrote:
>> I'll try to adjust the Debian / Ubuntu packaging scripts to meson.
> I tried to adjust the Ubuntu v4l-utils development scripts on top of the
> ariel/mesonbuild-v4 git branch.
> 
> On Unbuntu 20.04 I did the following:
> 
> mkdir v4l-meson
> cd v4l-meson
> git clone https://gitlab.com/adalessandro/v4l-utils.git
> git clone https://git.launchpad.net/\~libv4l/+git/v4l-utils-packaging
> cd v4l-utils
> git checkout ariel/mesonbuild-v4

Let's work on top of this branch:

    https://gitlab.com/adalessandro/v4l-utils/-/tree/v4l-utils-1.20.0-meson-v1

This is the one related to the submitted patch. Further changes will be pushed
to this branch.

> ln -s ../v4l-utils-packaging debian
> cd debian
> git checkout meson-build
> cd ..
> dpkg-buildpackage -uc -b -rfakeroot # install build-essential + missing
> 
> I noticed the following:
> * library symlinks are not in place
>   see https://packages.debian.org/sid/amd64/libv4l-0/filelist

Right. Each library target should have soversion and version set in order to
create the proper symlinks. As follows:

    diff --git a/lib/libdvbv5/meson.build b/lib/libdvbv5/meson.build
    index 6bbde1b0..8854a801 100644
    --- a/lib/libdvbv5/meson.build
    +++ b/lib/libdvbv5/meson.build
    @@ -137,6 +137,8 @@ libdvbv5_c_args = [

     libdvbv5 = library('dvbv5',
                        libdvbv5_sources,
    +                   soversion: '0',
    +                   version: '0.0.0',
                        install : true,
                        dependencies : libdvbv5_deps,
                        c_args : libdvbv5_c_args,

BTW, shall we set these fields in meson with the proper version tag?

> 
> * static libraries are missing

Libraries are defined in the meson scripts as `library`, so they can be built as
static, shared or both, depending on the configuration option `default_library`
(defaults to shared). I think this is fine and we should explicitly set the
option -Ddefault_library=both.

For example, in v4l-utils-packaging:

    diff --git a/rules b/rules
    index 60f86bf..84a4abb 100755
    --- a/rules
    +++ b/rules
    @@ -8,6 +8,7 @@ export DEB_BUILD_MAINT_OPTIONS = hardening=+bindnow
     #CONFIGURE_FLAGS += --enable-doxygen-man --disable-doxygen-ps
--disable-doxygen-pdf
     CONFIGURE_FLAGS += -Dqvidcap=disabled
     CONFIGURE_FLAGS += -Dbpf=disabled
    +CONFIGURE_FLAGS += -Ddefault_library=both

     %:
            dh $@ --buildsystem=meson+ninja

> 
> * bfd sources did not compile properly (now disabled in my repo):
> 
>> cd obj-x86_64-linux-gnu && LC_ALL=C.UTF-8 meson .. --wrap-mode=nodownload
>> --buildtype=plain --prefix=/usr --sysconfdir=/etc --localstatedir=/var
>> --libdir=lib/x86_64-linux-gnu -Dlibv4lconvertsubdir=libv4lconvert0
>> -Dqvidcap=disabled
>>
>> [122/274] /usr/bin/meson --internal exe --unpickle
>> /home/gregorj/src/v4l-meson/v4l-utils/obj-x86_64-linux-gnu/meson-private/meson_exe_clang_8e74c7d634462a79ae20aa67cb5c690cf72447f7.dat
>>
>> FAILED: utils/keytable/bpf_protocols/manchester.o /usr/bin/meson --internal
>> exe --unpickle
>> /home/gregorj/src/v4l-meson/v4l-utils/obj-x86_64-linux-gnu/meson-private/meson_exe_clang_8e74c7d634462a79ae20aa67cb5c690cf72447f7.dat
>>
>> In file included from ../utils/keytable/bpf_protocols/manchester.c:5:
>> In file included from /usr/include/linux/lirc.h:10:
>> /usr/include/linux/types.h:5:10: fatal error: 'asm/types.h' file not found
>> #include <asm/types.h>
>>          ^~~~~~~~~~~~~
>> 1 error generated.

Fixed. Include directories were omitted by clang as they were all passed as a
single string from the script's output. This fixes the issue:

    diff --git a/utils/keytable/bpf_protocols/meson.build
b/utils/keytable/bpf_protocols/meson.build
    index 2f1ed072..88fb6cdf 100644
    --- a/utils/keytable/bpf_protocols/meson.build
    +++ b/utils/keytable/bpf_protocols/meson.build
    @@ -22,7 +22,7 @@ foreach file : bpf_protocols_files
                       input : input,
                       command : [
                           prog_clang.path(),
    -                      clang_sys_includes.stdout().strip(),
    +                      clang_sys_includes.stdout().split(),
                           '-D__linux__', '-target', 'bpf', '-O2',
                           '-c', '@INPUT@', '-o', '@OUTPUT@',

> 
> * doxygen targets are missing
>   see
> https://gitlab.com/adalessandro/v4l-utils/-/blob/ariel/mesonbuild-v4/m4/ax_prog_doxygen.m4

Will check.

Regards,
Ariel