This flag is removed for a few reasons:
* Engines universally set this flag to true for widths > 320,
which made it redundant everywhere;
* This flag functioned primarily as a "force 1x scaler" flag,
since its behaviour was almost completely undocumented and users
would need to figure out that they'd need an explicit non-default
scaler set to get a scaler to operate at widths > 320;
* (Most importantly) engines should not be in the business of
deciding how the backend may choose to render its virtual screen.
The choice of rendering behaviour belongs to the user, and the
backend, in that order.
A nearby future commit restores the default1x scaler behaviour in
the SDL backend code for the moment, but in the future it is my
hope that there will be a better configuration UI to allow users
to specify how they want scaling to work for high resolutions.
This is done for consistency so that all the games in the Magic Tales
series are named in a consistent way. This is also how they are named
on the wiki (and on amazon).
Recently we started to use this as new semantics, although in the past
we used simly <engine>_H. Now these guard defines are consistent with
rest of the files which are used in the engines.
Some backends like GCW0 do no support graphics >320x240 due to
the hardware limitation (downscaling is possible but it will ruin
the pixel hunting which is often part of the gameplay).
Instead of manually updating the list of engines, we now introduce
a new dependency.
I marked all relevant engines, but some, like tinsel, require more
work with putting their relevant high-res games under USE_HIGHRES
define.
Each engine now only has to provide a single configure.engine file
adding the engine into the configure script, which then produces the
required other files automatically.
This is the third and final commit enabling fully pluggable engines.
Now providing an engine folder contains a configure.engine, engine.mk
and engine-plugin.h file, it will be picked up automatically by the
configure script.
