Re: [PULL 29/86] meson: move libudev test

[Paolo Bonzini]

On 01/10/20 18:19, Peter Maydell wrote:
> Hi; this commit seems to have broken my static build.
> Previously configure did not include libudev in the link
> for a static build (there is no libudev.a, at least on my
> system). Now it does, and then the link fails with
>   /usr/bin/ld: cannot find -ludev
> 
>>  ##########################################
>> -# Do we have libudev
>> -if test "$libudev" != "no" ; then
>> -  if $pkg_config libudev && test "$static" != "yes"; then
>> -    libudev="yes"
>> -    libudev_libs=$($pkg_config --libs libudev)
>> -  else
>> -    libudev="no"
>> -  fi
>> -fi
>
> This is the old code, which doesn't enable libudev for
> static builds. [...]
> I'm not very confident about reading meson.build logic, but it
> looks like this trusts meson/pkg-config to tell it about
> whether it can do a static link against this library,
> which doesn't work on my system, at least. (Ubuntu 18.04.4).

Yes, and the same was of course true of pkg-config without meson.  You
probably got the same warning that you reported on v7.

In fact, my guess is that the "test $static != yes" was added in reply
to a similar complaint; the commit that introduced it has a note that
the test was added by the maintainer:

    commit 3efac6ebb88e4d099f07fef65178ebaa595ae770
    Author: Tomáš Golembiovský <tgolembi@redhat.com>
    Date:   Tue Oct 23 13:23:10 2018 +0200

    configure: add test for libudev

    Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
    Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
    *make libudev optional to avoid breaking existing build/test
    environments
    *disable libudev for --static builds
    Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

But I don't think --static should affect the build this way, especially
since libudev was the only library that had this test in the configure
script (checked in 5.1).  Debian doesn't package "libgtk-3.a" either and
yet GTK+ it is not special cased in the configure script, so I'm not
sure what it is that makes libudev special.

Do you actually build just with "--static"?  Or do you have a list of
"--disable" options so you can add one more?

Paolo