title: How to solve 'ambiguous import' when using go mod?
body: <p>I'm trying to run go-ethereum@v1.0.0 on my windows machine.</p>
  
  <p>What I do:</p>
  
  <pre><code>cd G:\go
  git clone https://github.com/ethereum/go-ethereum.git
  cd go-ethereum/cmd/geth
  git checkout tags/v1.0.0 -b v1.0.0
  go mod init github.com/ethereum/go-ethereum/cmd/geth
  go run .
  </code></pre>
  
  <p>I hope go mod can help me install all modules, but meet an error:</p>
  
  <pre><code>package github.com/ethereum/go-ethereum/cmd/geth: unknown import path "github.com/ethereum/go-ethereum/cmd/geth": ambiguous import: found github.com/ethereum/go-ethereum/cmd/geth in multiple modules:
          github.com/ethereum/go-ethereum/cmd/geth (G:\go\go-ethereum\cmd\geth)
          github.com/ethereum/go-ethereum v1.8.23 (G:\GOPATH\pkg\mod\github.com\ethereum\go-ethereum@v1.8.23\cmd\geth)
  </code></pre>
  
  <p>I think that's because the cmd/geth exists in $GOPATH and $PWD both. How can I solve this can run successfully?</p>
  
  <p>PS: I hope it use $PWD so that I can change it.</p>