macOS : Build error during brew install

[invartam]

Environment

macOS Mojave 10.14.6 go 1.13.1

Description

Here is the output I got when I ran brew install etcdtool :

[0][0][benjy@benjy-mac:~/local/var/lib]
$ brew install etcdtool
==> Installing etcdtool from mickep76/funk-gnarge
==> Downloading https://github.com/mickep76/etcdtool/archive/3.3.2.tar.gz
Already downloaded: /Users/benjy/Library/Caches/Homebrew/downloads/2c5ed62a0fe74cb017f87d9ed730b0a90463edf47cdcb9aebb409aa712d33e3b--etcdtool-3.3.2.tar.gz
==> ./build
Last 15 lines from /Users/benjy/Library/Logs/Homebrew/etcdtool/01.build:
github.com/xeipuuv/gojsonschema
runtime.main_main·f: function main is undeclared in the main package
# github.com/constabulary/gb/cmd/gb-vendor
github.com/constabulary/gb/cmd/gb-vendor
runtime.main_main·f: function main is undeclared in the main package
# github.com/constabulary/gb/cmd/gb
github.com/constabulary/gb/cmd/gb
github.com/ugorji/go/codec
github.com/coreos/etcd/client
github.com/mickep76/etcdmap
github.com/mickep76/etcdtool/command
runtime.main_main·f: function main is undeclared in the main package
# github.com/mickep76/etcdtool
github.com/mickep76/etcdtool
FATAL: command "build" failed: exit status 2

If reporting this issue please do so at (not Homebrew/brew or Homebrew/core):
  https://github.com/mickep76/homebrew-funk-gnarge/issues