Comment 10 for bug 1531508

@Dave, Re #6 above; I was for a few minutes pondering doing an Automake macro to detect the gcc version and use 'std=c++0x' for gcc versions < 4.7 from before the C++ standard was ratified and to use 'std=c++11' on more recent gcc, but I fear that's going to be time-consuming—although perhaps I could do a PR to the documentation to at least mention it.