Pull new version of protobuf sources.

third_party/protobuf/examples/README.txt

+This directory contains example code that uses Protocol Buffers to manage an
+address book.  Two programs are provided, each with three different
+implementations, one written in each of C++, Java, and Python.  The add_person
+example adds a new person to an address book, prompting the user to input
+the person's information.  The list_people example lists people already in the
+address book.  The examples use the exact same format in all three languages,
+so you can, for example, use add_person_java to create an address book and then
+use list_people_python to read it.
+
+You must install the protobuf package before you can build these.
+
+To build all the examples (on a unix-like system), simply run "make".  This
+creates the following executable files in the current directory:
+  add_person_cpp     list_people_cpp
+  add_person_java    list_people_java
+  add_person_python  list_people_python
+
+If you only want to compile examples in one language, use "make cpp"*,
+"make java", or "make python".
+
+All of these programs simply take an address book file as their parameter.
+The add_person programs will create the file if it doesn't already exist.
+
+These examples are part of the Protocol Buffers tutorial, located at:
+  https://developers.google.com/protocol-buffers/docs/tutorials
+
+* Note that on some platforms you may have to edit the Makefile and remove
+"-lpthread" from the linker commands (perhaps replacing it with something else).
+We didn't do this automatically because we wanted to keep the example simple.