install go yourself, it's easy

Package managers generally don't do diff updates, so every go version is just another huge download.

Thankfully, go is really easy to install and manage. And once you're up + running, git source code diffs are much smaller, and you're free to checkout whatever commit you want and recompile.

First, you need a go1.4 bootstrap and a C compiler; go1.4 is the last one with a C toolchain1. Once compiled, go1.4's used to bootstrap newer versions of go.

    curl -L -o- https://jrl.ninja/sw/go/go1.4-bootstrap-20171003.tar.xz | tar xJf -
    mv go go1.4-bootstrap
    cd go1.4-bootstrap/src
    CGO_ENABLED=0 ./make.bash

Then clone go and build it.

    git clone https://go.googlesource.com/go
    cd go/src
    GOROOT_BOOTSTRAP=$PWD/../../go1.4-bootstrap ./make.bash

1I don't know like, the minimum GCC version or what C standard go1.4 source complies to.