Mby will help for somebody. I'm on Fedora 29.
When I installed Go I did:
echo 'export GOPATH=$HOME/Go' >> $HOME/.bashrc
source $HOME/.bashrc
So I have my GOPATH set up.
Next I do:
echo 'export PATH=$PATH:$GOPATH/bin' >> $HOME/.bashrc
source $HOME/.bashrc
And my protoc
compiler work lika a charm.