usbguard: dpkg-shlibdeps warning

[Birger Schacht <birger@rantanplan.org>]

Hi,

when building usbguard, dpkg-shlibdeps warns me about an unresolvable
refernce to pthread_create:

> dpkg-shlibdeps: warning:
debian/libusbguard0/usr/lib/x86_64-linux-gnu/usbguard/libusbguard.so.0.0.0
contains an unresolvable reference to symbol pthread_create: it's
probably a plugin

The manpage says:
> If the binary is really a plugin, then disregard this warning. But
> there's always the possibility that it's a real library and that
> programs linking to it are using an RPATH so that the dynamic loader
> finds it.
> In that case, the library is broken and needs to be fixed.

The package is indeed using RPATH, because the lib is not stable yet and
is installed in /usr/lib/<triplet>/usbguard. But I'm totally lost on how
to fix the dpkg-shlibdeps warning, I don't even understand the problem.
Can anyone shed some light on this issue?

Thanks,
Birger