Hello. After some brainstorming and some help from a mingw.org user we managed to get gcc building again with pthreads-w32. Theres a few changes needed, first and foremost windows.h must not be included in pthread.h, i used a guard to only allow it at build time but it should newer be allowed if we want to do this correctly since it breaks gcc macros. Secondly the check for __MINGW64__ is wrong since __MINGW64__ == __MINGW32__ if you want to distinguish the builds for the mingw-w64 compiler the correct define is __MINGW64_VERSION_MAJOR. Rest of the changes are against gcc itself and have been pushed to the gcc dev team. Im not sure where to submit patches for pthreads-w32 since the repository is read only, but i can forward them to you if you prefer it that way. Let me know which option would be preferable. Regards Ralph Engels