Portability problems fixed by Gnulib module @code{getopt-gnu}:
@itemize
@item
+This function is missing on some platforms:
+MSVC 9.
+@item
The function @code{getopt} does not support the @samp{+} flag in the options
string on some platforms:
MacOS X 10.5, AIX 5.2, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11 2010-11.
Solaris 11 2010-11, Cygwin 1.5.x.
@item
The function @code{getopt_long} is missing on some platforms:
-AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Interix 3.5.
+AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, MSVC 9, Interix 3.5.
@item
The function @code{getopt_long_only} is missing on some platforms:
MacOS X 10.3, FreeBSD 5.2.1, NetBSD 5.0, AIX 5.1, HP-UX 11, IRIX 6.5,
-OSF/1 5.1, Solaris 9, mingw, Interix 3.5.
+OSF/1 5.1, Solaris 9, mingw, MSVC 9, Interix 3.5.
@item
This function crashes if the option string includes @code{W;} on some
platforms: