https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80658
--- Comment #12 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Bernd Paysan from comment #11) > My guess. He mentions that he's not a lone wolf coder, and since he didn't > understand why mt_allocator was active, I guessed that a coworker had > enabled it ;-). There's no trace at all of ext/mt_allocator in the source > code on github, but in a crappy project, you never know if they build from > the sources they released to github. Yeah I checked that too. > However, with the CPP/CXX change of the environment variable: The minimal > GCC version that builds this project is GCC 4.9... or clang 3.9, which it > prefers to use on build if both gcc and clang are available. So it can't > use a too old libstdc++. In which case using GLIBCXX_FORCE_NEW means they are intentionally switching to a custom allocator in production without testing if it works, and then blaming libstdc++. Or they're linking to some 3rd party library build with an ancient libstdc++. Or setting the env var was just voodoo and didn't change anything in libstdc++. So I still see nothing close to a useful bug report, and I've wasted several hours that could have been spent fixing real bugs in the current codebase.