package/libnetfilter_queue: fix build with musl

Backport a patch from upstream.

Fixes:
    http://autobuild.buildroot.org/results/59b/59bd31c10a0d445d2ea56550a36920ecb2ef89ed/
    http://autobuild.buildroot.org/results/60a/60ab98b4cf909b04a57207b2326e9f8080d1721b/
    http://autobuild.buildroot.org/results/7db/7db3a5c2bebabfdc26947f45382893bb14656617/



Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>