Portability problems fixed by Gnulib:
@itemize
@item
+This function is missing on some platforms:
+AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, MSVC 9, Interix 3.5.
+@item
+The function @code{getopt_long} does not obey the combination of
+@samp{+} and @samp{:} flags in the options string on some platforms:
+glibc 2.11.
+@item
+The use of @samp{W;} in the optstring argument to does not always
+allow @code{-W foo} to behave synonymously with @code{--foo}:
+glibc 2.11.
+@item
The function @code{getopt_long} does not support the @samp{+} flag in
the options string on some platforms:
MacOS X 10.5, AIX 5.2, OSF/1 5.1, Solaris 10.
@item
+The value of @code{optind} after a missing required argument is wrong
+on some platforms:
+MacOS 10.5.
+@item
The function @code{getopt_long} does not obey the @samp{-} flag in the
options string when @env{POSIXLY_CORRECT} is set on some platforms:
Cygwin 1.7.0.
@item
+Some implementations fail to reset state, including re-checking
+@env{POSIXLY_CORRECT}, when @code{optind} is set to @samp{0}:
+NetBSD, Cygwin 1.7.0.
+@item
The function @code{getopt_long} does not support options with optional
arguments on some platforms:
-MacOS X 10.5, OpenBSD 4.0, AIX 5.2, IRIX 6.5, Solaris 10, Cygwin 1.5.x.
+MacOS X 10.5, OpenBSD 4.0, AIX 5.2, IRIX 6.5, Solaris 11 2010-11, Cygwin 1.5.x.
@item
-This function is missing on some platforms:
-AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Interix 3.5.
+This function crashes if the option string includes @code{W;} but
+there are no long options, on some platforms:
+glibc 2.14.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
-@item
-The glibc implementation allows a complete reset of the environment,
-including re-checking for @env{POSIXLY_CORRECT}, by setting
-@code{optind} to 0. Other implementations provide @code{optreset},
-causing a reset by setting it non-zero, although it does not
-necessarily re-read @env{POSIXLY_CORRECT}.
@end itemize