This patch adds a new "accept" promise that allows you to call accept()
on an already listening socket. This lets programs set up a socket for
for listening and then dropping "inet" and/or "unix" so that only
incoming (and existing) connections are allowed from that point on.
No new outgoing connections or listening server sockets can be created.
In addition to accept() it also allows getsockopt() with SOL_SOCKET
and SO_PEERCRED, which is used to find the PID/UID/GID of the socket
peer. This is used by our IPC library when creating shared buffers that
should only be accessible to a specific peer process.
This allows us to drop "unix" in WindowServer and LookupServer. :^)
It also makes the debugging/introspection RPC sockets in CEventLoop
based programs work again.
Now that the "unix" pledge is no longer required for socket I/O, we can
drop it after making the connections we need in a program.
In most GUI program cases, once we've connected to the WindowServer by
instantiating a GApplication, we no longer need "unix" :^)
We now try to open image files dropped on us from FileManager. :^)
The QuickShow code is not exactly well-factored, and should be fixes up
to not do the same thing twice, etc.
This behavior and API was extremely counter-intuitive since our default
behavior was for applications to never exit after you close all of their
windows.
Now that we exit the event loop by default when the very last GWindow is
deleted, we don't have to worry about this.
Instead of LibGUI and WindowServer building their own copies of the drawing
and graphics code, let's it in a separate LibDraw library.
This avoids building the code twice, and will encourage better separation
of concerns. :^)
This needs more work and polish, but it's a step in a more pleasant and
useful direction.
Also turn QuickShow into a fully-fledged "application". (By that, I really
just mean giving it its own Applications/ subdirectory.)
