Closures in C

GCC and Clang. The syntax is ugly, but hell, it's C. Oh, and this is Apple's work, bumping their total number of useful contributions to computing to a whopping 2 (3 if you count Squeak; much of its development was at Disney).

http://lists.cs.uiuc.edu/pipermail/cfe-dev/2008-August/002670.html

>>2
Not everyone has the luxury of choosing a language for the projects they work on. Teams, legacy code, libraries, corporate policies, etc.