Install Protobuf on OSX (aws#207)

Author: NihalHarish

config/protoc_downloader.sh

@@ -1,7 +1,17 @@
 #!/bin/bash
-apt-get install sudo
-sudo apt-get install unzip
-PROTOC_ZIP=protoc-3.7.1-linux-x86_64.zip
+unameOut="$(uname -s)"
+case "${unameOut}" in
+    Linux*)     machine=Linux;;
+    Darwin*)    machine=Mac;;
+esac
+if [ "$machine" = "Mac" ] ; then
+    PROTOC_ZIP=protoc-3.7.1-osx-x86_64.zip
+    brew install unzip
+else
+    PROTOC_ZIP=protoc-3.7.1-linux-x86_64.zip
+    apt-get install sudo
+    sudo apt-get install unzip
+fi
 curl -OL https://github.com/google/protobuf/releases/download/v3.7.1/$PROTOC_ZIP
 unzip -o $PROTOC_ZIP -d /usr/local bin/protoc
 unzip -o $PROTOC_ZIP -d /usr/local include/*