package/cdrkit: fix musl build

Define __THROW if not already defined by the C library.

Fixes:
http://autobuild.buildroot.net/results/d27/d2781e70b04a207e2e9397d888032294c7285034/



Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>