While starting a protobuf compiler I learned a little about autoconf. First it complains about version the protobuf code was using automake 1.10.1 and I had 1.7.9. so I upgraded to automake using “sudo apt-get install automake1.10″. Of course this upgraded my automake to 1.10.2 which still didn’t work.The solution was to run autoconf from the path/to/protobuf-2.1.0 but that didn’t work until I used “sudo apt-get libtool” to get the latest libtool. This uses the configure.ac and then generated Makefile.in from the Makefile.am.