Thrift: Update to 0.9.1 and fix build on OS X 10.9

This combines all the changes that #25308 and #24237 made into one pull request (feel free to close this if either updates & sorry for the noise in that case). Summary of changes:

* Bump thrift to 0.9.1
* Use C++11 and patch it to build on clang (required for 10.9)
* Add the dependency to pkg-config that `--HEAD` needs to build cleanly.