It appears that change 02a01ead in pkg-golang/golang.git backed out alternatives support: https://anonscm.debian.org/cgit/pkg-golang/golang.git/commit/?h=golang-1.6&id=02a01eadb65fa19631ed5a8c491d70c212e0ec96
I cannot readily determine why (from either the Debian or Ubuntu bug trackers.)
