[nix-shell:~/Downloads/zig/build]$ grep -IR mkdir ../lib/libc/include/any-windows-any/
../lib/libc/include/any-windows-any/tchar.h:#define _tmkdir _wmkdir
../lib/libc/include/any-windows-any/tchar.h:#define _tmkdir _mkdir
../lib/libc/include/any-windows-any/wchar.h:  _CRTIMP int __cdecl _wmkdir(const wchar_t *_Path);
../lib/libc/include/any-windows-any/direct.h:  _CRTIMP int __cdecl _mkdir(const char *_Path);
../lib/libc/include/any-windows-any/direct.h:  _CRTIMP int __cdecl _wmkdir(const wchar_t *_Path);
../lib/libc/include/any-windows-any/direct.h:  int __cdecl mkdir(const char *_Path) __MINGW_ATTRIB_DEPRECATED_MSVC2005;
../lib/libc/include/any-windows-any/io.h:  int __cdecl mkdir (const char *) __MINGW_ATTRIB_DEPRECATED_MSVC2005;