Debug assertion and constexpr

[François Dumont]

Hello

    There are at the moment several failures in the libstdc++ testsuite
when run in debug mode (_GLIBCXX_DEBUG). This is so because debug
assertions are not const expressions. Several debug assertions have been
removed because of this issue.

    So is there a way to define a function as to be ignored in the
context of a const expression ? If not could we add one ?

François