build: Do not warn about C99 extensions

Change-Id: Id2a612391120f0eeee9f527c633f49581afed47d
Refs: #1865
encoding: Adding missing include

Change-Id: Ib7de4d7112eb3f8104449c5a71a63275a82cafda
Refs: #1864
util: Ensure ndn::RegexComponentMatcher works with Boost >= 1.56

Change-Id: I39c2c400317cf00a9a560e0b9d26f786ea5e3486
Refs: #1866