http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54757
--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-09-30 13:14:25 UTC --- Simply, atan2 is C89, hypot is C99. Confirmed that we don't have to do anything special besides making sure that C99 functions like hypot aren't used when _GLIBCXX_USE_C99_MATH_TR1 is not defined. In particular, we definitely don't want to fiddle with the global namespace, a sure recipe for maintainance nightmare.
