mknodat
=======

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/mknodat.html

Gnulib module: mkfifoat

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: glibc 2.3.6, macOS 11.1, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 10, Cygwin 1.5.x, mingw, MSVC 14, Android 4.4. But the replacement function is not safe to be used in libraries and is not multithread-safe.

  * This function does not fail when the file name argument ends in a slash and (without the slash) names a nonexistent file, on some platforms: AIX 7.2.

Portability problems not fixed by Gnulib:

  * The gnulib replacement function always fails with ENOSYS on some platforms: mingw, MSVC 14.

  * If the argument exists and is a directory, the gnulib replacement function fails with EISDIR instead of the correct EEXIST: HP-UX 11.11.