[SOLVED] Build packetbeat on windows

I have just tried to build packetbeat again from my mac, I cloned the new beats with git clone https://github.com/elastic/beats
From src/github.com/elastic/beats/packetbeat I can run make without any errors but running make crosscompile for darwin and windows gives me this error:

go get github.com/mitchellh/gox
mkdir -p build/bin
gox -output="build/bin/{{.Dir}}-{{.OS}}-{{.Arch}}" -os="darwin windows" 
Number of parallel builds: 7

-->   windows/amd64: github.com/elastic/beats/packetbeat
-->    darwin/amd64: github.com/elastic/beats/packetbeat
-->     windows/386: github.com/elastic/beats/packetbeat
-->      darwin/386: github.com/elastic/beats/packetbeat

4 errors occurred:
--> darwin/amd64 error: exit status 2
Stderr: # github.com/elastic/beats/packetbeat/sniffer
sniffer/sniffer.go:26: undefined: pcap.Handle
sniffer/sniffer.go:31: undefined: pcap.Dumper

--> windows/amd64 error: exit status 2
Stderr: # github.com/elastic/beats/packetbeat/sniffer
sniffer/sniffer.go:26: undefined: pcap.Handle
sniffer/sniffer.go:31: undefined: pcap.Dumper

--> darwin/386 error: exit status 2
Stderr: # github.com/elastic/beats/packetbeat/sniffer
sniffer/sniffer.go:26: undefined: pcap.Handle
sniffer/sniffer.go:31: undefined: pcap.Dumper

--> windows/386 error: exit status 2
Stderr: # github.com/elastic/beats/packetbeat/sniffer
sniffer/sniffer.go:26: undefined: pcap.Handle
sniffer/sniffer.go:31: undefined: pcap.Dumper

make: *** [crosscompile] Error 1

Can anyone see what I am missing and how the get past this message?