This function is missing on some platforms; however, the replacement
fails on symlinks if @code{chown} is supported, and fails altogether
with @code{ENOSYS} otherwise:
-MacOS X 10.3, mingw, BeOS.
+MacOS X 10.3, Minix 3.1.8, mingw, MSVC 9, BeOS.
@end itemize
Portability problems not fixed by Gnulib: