GXemul: Release notes

# Release notes for GXemul 0.6.3.1

Copyright (C) 2003-2021 Anders Gavare

GXemul is a framework for full-system computer architecture emulation. Several processor architectures and machine types have been implemented. It is working well enough to allow unmodified "guest" operating systems to run inside the emulator, as if they were running on real hardware.

The emulator emulates (networks of) real machines. The machines may consist of ARM, MIPS, Motorola 88K, PowerPC, and SuperH processors, and various surrounding hardware components such as framebuffers, busses, interrupt controllers, ethernet controllers, disk controllers, and serial port controllers.

The documentation lists the machines and guest operating systems that can be regarded as "working" in GXemul. The first guest operating system that worked in GXemul was NetBSD/pmax on an emulated DECstation 5000/200, and that is still one of the guest OSes that works best.

The most important changes between release 0.6.3 and 0.6.3.1 are:

- Many small fixes that allow OpenBSD/luna88k to run better, including running X11.

- A bug regarding checking the return value from `select()` calls when detecting whether console input was available has now been fixed. This bug resulted in spuriously broken interactivity on some systems (at least Linux), e.g. when typing CTRL-C to enter the GXemul command prompt, which required extra keypresses.

The most important changes between release 0.6.2 and 0.6.3 are:

- OpenBSD/luna88k can now run in GXemul with root-on-nfs. The installation instructions are somewhat involved, but it works well enough to self-compile at least an older version of GXemul inside OpenBSD running in the emulator.

- /dev/tap devices in the host can now be used for networking. (Patch contributed by Jason Thorpe.)

- A bug which caused reads at the end of files supplied as disk images to fail has been fixed. Usage of tar archives for passing files to and from emulated machines that lack networking capability is thus somewhat less buggy.

Please read the HISTORY file for more details.

To build the emulator, run the `configure` script, and then run `make`. This should hopefully work on most Unix-like systems, with few or no modifications to the source code.

Regarding files in the `src/include/thirdparty/` directory: most of these are from other open source projects such as NetBSD. See individual source files for details, if you plan to redistribute GXemul in binary form, or reuse the source code.

GXemul's homepage is http://gavare.se/gxemul/.