include protoc requirement in bootstrap & readme

README.md

@@ -32,7 +32,13 @@ Server APIs:
 
 ### From source
 
-Ensure Go 1.15+ is installed, and GOPATH/bin is in your PATH.
+Pre-requisites:
+
+* Go 1.15+ is installed
+* GOPATH/bin is in your PATH
+* [protoc](https://grpc.io/docs/protoc-installation/) is installed and in PATH
+
+Then run
 
 ```shell
 git clone https://github.com/livekit/livekit-server

bootstrap.sh

@@ -1,5 +1,11 @@
 #!/bin/bash
 
+if ! command -v protoc &> /dev/null
+then
+  echo "protoc is required and not found. please install"
+  exit 1
+fi
+
 if ! command -v mage &> /dev/null
 then
   pushd /tmp