Both GCC and Clang, though the code is still relatively untested.
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2008-August/002670.html
Isn't this called Objective C?
shit syntax, and no, it won't make it to the C1x standard.
Yeah, I think it's unlikely they'll show up in C1x, but not because of the syntax, but because of the reliance on some underspecified allocator and mmu protection bits problems.
Closures are SORELY needed in Objective-C! This is great news on that front.
C1X you say! I can hardly wait until 2019 rolls around.