The problem with libc++ the last time I tried it was that it was heavily focused on MacOS, and didn't even build out of the box on Linux.
Maybe they've fixed this by now, I dunno. [Though the wording in that blurb, "100% complete C++11 implementation on Apple's OS X" doesn't inspire confidence...]
I don't know about GCC, but Clang (at least on OS X) lets you select the stdandard library with the -stdlib option. So the only question is whether you can use libc++ with GCC.
When I did research on this a year or two ago the GCC folks told me that GCC is highly coupled to libstdc++ and that it is not really interchangeable. I am not sure if this has changed more recently.
Clang definitely lets you easily switch between libstdc++ and libc++.
I can confirm you can use libc++ with gcc. I've already built a couple projects with it. It was the only way I could get past the linker step, once I included any c++11 standard library functions...
according to its release page clang 3.3 (due for release next wednesday) is also C++11 feature complete and apparently has implementations for several c++1y features already.
And perhaps more importantly, clang is the only project with a full implementation of the C++11 standard library. GCC supports the language but libstdc++ is not all the way there yet.
Happens all the time. It used to be worse because there wasn't a duplicate submit feature. You'd see two posts that were 20 minutes apart and the second one caught people's attention. It only takes a couple upvotes before others will take a look.
There were a HN story a few weeks ago about how to maximize the chance for front page. Some days are better than others, as well as what time of the day.
http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#s...