Besides the obvious limitation of being unavailable on Windows,
the standard is vague about getopt() and getopt_long() has many
non-portable pitfalls and buggy implementations, that increase
the maintainance cost a lot. Also the GNU libc code currently
in the tree is not suited for embedding and is unmaintainable.
Own maintainership for getopt_long() and use the musl implementation
everywhere. This way we don't need to worry if optreset is available,
or if the $OPERATING_SYSTEM version behaves in subtly different ways.
The API is under the Wireshark namespace to avoid conflicts with
system headers.
Side-note, the Mingw-w64 9.0 getopt_long() implementation is buggy
with opterr and known to crash. In my experience it's a headache to
use the embedded getopt implementation if the system provides one.
João Valverde