This makes it easier to understand the code, avoids conflicts
and ugly and unnecessary casts.

The field display enum has evolved over time from integer types
to a type generic parameter.

C is notoriously difficult to bind from other languages
without additional metadata. The C ABI does not include
enums and macros that are an essential component of the
API.

To make Wireshark instrospectable and more binding friendly
include an introspection API to export enums and integer macros.

To avoid the tedious need to manually keep the code up to date
it uses the excellent pyclibrary python package to automatically
parse C headers and extract this data.

This is not a process that should be done automatically during
the build.

This could be used for example to replace most of the wslua
make-init-lua.pl perl script, which tries to do the same thing
using regular expressions.

Besides the downside of using Perl using regular expressions
is inferior to pyclibrary in 2 ways: 1) pyclibrary understands
most of C99 grammar so it is much more powerful; 2) pyclibrary
has a specific API to extract "values" (enums and constants)
automagically. We just need to take care to use only integer
values, for our purposes.

PCRE2 is the future of PCRE. The only advantage of GRegex is that
it comes bundled with GLib, which is not an advantage at all.
PCRE2 is widely available, the GRegex abstractions layer are not a
good fit and abstract things that don't need abstracting or that we
could handle better ourselves, there are open bugs (#12997) and
maintenance is spotty at best.

GRegex comes with many of the problems of bundled code, aggravated by
the fact that it completely falls outside of our control.

Move dissectors.c to a separate object library so that the rest of the
dissectors don't have to wait for it to be generated. This reduces build
time here by a few seconds when ccache is enabled.

This patch adds basic dissection for the egfx channel. It also fixes fragmentation
in the dynamic channel, and also introduces some of the decompressors involved in RDP
traffic.