Deactivate the msgpack option. The binutils build might detect the
libmsgpackc.so.2 library and will try to link against it, if it is not
explicitly deactivated.
This prevents the following build errors seen in the build bots.
Package binutils is missing dependencies for the following libraries:
libmsgpackc.so.2
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
d9a00c5e2d