Download mosh and libprotobuf:
wget http://mosh.mit.edu/mosh-1.2.4.tar.gz
wget https://protobuf.googlecode.com/files/protobuf-2.5.0.tar.bz2
Build and install protobuf:
tar xfvj protobuf-2.5.0.tar.bz2
cd protobuf-2.5.0
./configure --prefix=$HOME