https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80881 --- Comment #9 from Daniel Starke <daniel.f.starke at freenet dot de> --- This was a native build. I have added the GCC build in question to https://sourceforge.net/projects/gcc-win64/files/7.1.0/gcc-7.1.0-debug-broken-tls.7z