Portability problems fixed by Gnulib:
@itemize
@item
+This function mistakenly removes a directory with
+@code{rmdir("dir/./")} on some platforms:
+Cygwin 1.5.x.
+@item
+This function fails with @code{EINVAL} instead of the expected
+@code{ENOTDIR} for @code{rmdir("file/")} on some platforms:
+mingw.
+@item
This function is missing on some old platforms.
@end itemize
@item
When @code{rmdir} fails because the specified directory is not empty, the
@code{errno} value is system dependent.
+@item
+POSIX requires that @code{rmdir("link-to-empty/")} remove @file{empty}
+and leave @file{link-to-empty} as a dangling symlink. This is
+counter-intuitive, so some systems fail with @code{ENOTDIR} instead:
+glibc
@end itemize