Squashed 'build-common/' changes from 667edee..d356b1b

d356b1b always use gtests tr1/tuple
8e9db39 make sure tests link w/threads lib

git-subtree-dir: build-common
git-subtree-split: d356b1b2f75c8078387e3e941af6c39154277cc0
Update build common
Merge pull request #10 from genome/gtest-tuples

fix gtest issues w/recent OS X compilers