meson: do not link libshared dynamically against libudev (#5850)
Linking dynamically against libudev will fail once
https://github.com/mesonbuild/meson/pull/1545 is merged and apparently
already triggers a link failure on s390x.
Make libshared provide the udev symbols by including libudev_sources
into libshared. This will cause those files to be compiled twice, but it
actually reduces the installed size and is closer to what the autotools
build system is doing.