New branch for STL Advisor

[Paolo Carlini]

> libstdc++-v3 maintainers, could you please comment/advise?

Can you explain which is the role of the debug-mode code, here? Because certainly the *performance* of the debug-mode library have *nothing* to do with the performance of the "real" library (whether that could be improved, tweaked, or whatever, is another issue, already raised in the past). Or are you planning to use the debug-mode code only for *counting* the calls, etc, no actual timings?

Paolo.