package/zeromq: disable -Werror
This will avoid the following build failure with openpgm 5.3:
In file included from /home/fabrice/buildroot/output/host/bin/../arm-buildroot-linux-gnueabihf/sysroot/usr/include/pgm-5.3/pgm/skbuff.h:39,
from /home/fabrice/buildroot/output/host/bin/../arm-buildroot-linux-gnueabihf/sysroot/usr/include/pgm-5.3/pgm/msgv.h:33,
from /home/fabrice/buildroot/output/host/bin/../arm-buildroot-linux-gnueabihf/sysroot/usr/include/pgm-5.3/pgm/pgm.h:44,
from src/ip.cpp:67:
/home/fabrice/buildroot/output/host/bin/../arm-buildroot-linux-gnueabihf/sysroot/usr/include/pgm-5.3/pgm/socket.h:207:1: error: ‘const char* pgm_family_string(int)’ defined but not used [-Werror=unused-function]
207 | pgm_family_string (
| ^~~~~~~~~~~~~~~~~
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>