gvim - fatal error: can't find import: fmt?

I have setup go related environment variables in my ~/.bashrc as follows

GOROOT=$HOME/go
GOOS=linux
GOARCH=amd64
GOBIN=$HOME/bin
export GOROOT GOOS GOARCH GOBIN PATH

When I compile from vi (:make) in terminal, everything is fine. However, when I do the same from gvim (window), I was getting

fatal error: can't find import: fmt

A quick google search pointed me to this

So, gvim is not seeing those environment variables. I confirm in gvim with

:echo $GOROOT

Reports an empty string. So I edit $MYVIMRC (:e $MYVIMRC) and add the following

:let $GOROOT='/home/amitava/go'
:let $GOARCH='amd64'
:let $GOOS='linux'

Worked like a charm!