From https://github.com/golang/go/wiki/GoArm : In cross compilation situations, it is recommended that you always set an appropriate GOARM value along with GOARCH. The value seems to default to GOARM=5 if not set during cross-compilation.
Fedora 28 executes A LOT of stuff from /usr/share/Modules/ on bash startup. Having -x in the shebang means we see it all.
Dup2 is not implemented on linux/arm64. Fixes https://github.com/rfjakob/gocryptfs/issues/121 . Also adds cross-compilation to CI.