https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91595
--- Comment #9 from Iain Buclaw <ibuclaw at gdcproject dot org> --- (In reply to Brecht Sanders from comment #8) > predefs GNU D_Version2 LittleEndian GNU_SEH_Exceptions GNU_EMUTLS > GNU_StackGrowsDown GNU_InlineAsm D_LP64 D_PIC assert D_ModuleInfo > D_Exceptions D_TypeInfo all X86_64 D_HardFloat Windows MinGW Win64 > CppRuntime_Gcc So there's no predefined CRuntime_* version condition, which is where all the missing definitions are hidden behind. Would MinGW be a CRuntime_Glibc target, a CRuntime_Microsoft target, or using it's own C library that has little commonality with neither glibc nor msvc?