MULTI-PLATFORM SUPPORT FOR MEGAZEUX

The arch/ directory structure contains any code/machinery which is platform
specific. Though is it dubiously named "arch" this refers to the platform
"architecture" rather than the CPU architecture. For example, although GP2X
and NDS both use ARM CPUs, they require different library and build system
machinery to work correctly.

DIRECTORY LAYOUT

Most directories here contain at least a README file describing what toolchain
and dependencies they require to work correctly. Some might also define
additional targets, for post-processing binaries or installing them on the
system.

Additionally, all of these directories must have a Makefile.in which the build
system will automatically include. This file should initialize any variables
that can be tweaked, for example the location of libraries or compiler flags.
The existing Makefile.in files should be a reasonable guide to this
functionality.

ADDING A PLATFORM TO MEGAZEUX

Adding support for a new platform is trivial. Think of a short name for the
platform (for example, Nintendo Dual-Screen is "nds") then create a directory
in arch/ with that name. Create a Makefile.in for your platform. Initially,
you may find configuring for "unix" and then manually altering the
"platform.inc" in the top level is enough to get your build to succeed.

Then, some changes must be made to config.sh to automatically generate both
the src/config.h header (which is fully generic) and the platform.inc. This
script is what users of your port will invoke to build the package.

You may also want to make sure the "build" and "archive" targets do something
for your platform. These targets make auto-builds and shipping binary
packages much easier.

LICENSES

If your port requires reporting extra software licenses, you should put a
notification in LICENSE.3rd. If the boilerplate isn't reasonably small, it
should go in this folder named in the format "LICENSE.[license here]". In this
situation, add the license filename to EXTRA_LICENSES so it will be shipped
with relevant builds.
