[FFmpeg-user] configure gives "ERROR: libzmq >= 4.2.1 not found using pkg-config"

[Moritz Barsnick]

On Wed, Feb 23, 2022 at 22:41:46 +0100, Reindl Harald wrote:
> > https://packages.debian.org/bullseye/arm64/libzmq3-dev/filelist
>
> and you think "libzmq3-dev" is >= 4.2.1?
> why?
>
> "ERROR: libzmq >= 4.2.1 not found using pkg-config"

Because that is what its pkg-config file claims:

-----
$ ar -p libzmq3-dev_4.3.4-1_arm64.deb data.tar.xz | tar xOJvf - \*libzmq.pc
./usr/lib/aarch64-linux-gnu/pkgconfig/libzmq.pc
prefix=/usr
exec_prefix=${prefix}
libdir=${prefix}/lib/aarch64-linux-gnu
includedir=${prefix}/include

Name: libzmq
Description: 0MQ c++ library
Version: 4.3.4
Libs: -L${libdir} -lzmq
Libs.private: -lstdc++  -lpthread -lrt
Requires.private:  krb5-gssapi libsodium openpgm-5.3 >= 5.3 norm libbsd
Cflags: -I${includedir}
-----

Name is libzmq, Version is 4.3.4. That should be >= 4.2.1.

I assume something else is wrong, like the pkg-config path not being
evaluated.

The output of
$ pkg-config --modversion libzmq
would be interesting, but presumably libzmq isn't found. I wonder how
to debug remotely what pkg-config is doing, if that dev package is
"correctly" installed.

Moritz