How to enable C++11/C++0x support in Eclipse CDT?

Question

Eclipse 3.7.1 CDT 1.4.1 GCC 4.6.2

This is an example of a piece of C++11 code:

auto text = std::unique_ptr(new char[len]);

Answer 1

Neither the hack nor the cleaner version work for Indigo. The hack is ignored, and the required configuration options are missing. For no apparent reason, build started working after not working and not providing any useful reason why. At least from the command line, I get reproducible results.