Cross-platform go builds with linux as a target platform and race
enabled require to link against the linux so and have the cross
platform compiler installed, which is a pain. To avoid this we
build everything in Linux-native environment in a container.
Note that running such builds requires replacing the operator
Docker base image from Alpine to something with a real glibc
(i.e. ubuntu), since the target binary needs a dynamic linker.
Use -a flag in order to rebuild all packages, since we might have
built them on a wrong platform.