Command:
protoc --plugin=/usr/local/bin/protoc-gen-objc test.proto
messages.proto empty.proto
--proto_path=/Users/jcanizales/git/protobuf-objc/src/compiler
--proto_path=. --objc_out="./"

Generated with:
protoc --plugin=/usr/local/bin/protoc-gen-objc route_guide.proto
--proto_path=/Users/jcanizales/git/protobuf-objc/src/compiler
--proto_path=. --objc_out="./"

On account of the change in the podspec structure.