CMake already distributes FindSDL*.cmake files for SDL and SDL_mixer,
which support custom prefixes via environment variables, removing the
need for ad-hoc logic in Win9x builds.
Also, according to FindSDL.cmake, #include <SDL.h> is the preferred way
for portability reasons, instead of #include <SDL/SDL.h>, which is the
option that has been used so far.
`gui` was tighly coupled to game logic, and could not be extended for
other purposes. Therefore, a generic GUI implementation, loosely
inspired by well-known GUI frameworks such as GTK, is now provided, with
the following properties:
- Does not depend on dynamic or static memory allocation, only automatic
(i.e., stack) memory allocation required.
- Portable among existing implementations.
- Simple to extend.
- Tiny memory footprint.
`gui` is now composed by GUI elements that can be chained to form a tree
structure. This is useful e.g.: to calculate X/Y coordinates for a given
GUI element given its parent(s).
This commit also refactors the older implementation, moving
game-specific logic into `player` and making use of the new component.
This has several advantages:
- `camera` no longer needs to define public functions for each
peripheral type.
- Peripheral-related is now no longer tighly coupled to human_player,
so peripheral logic can be reused elsewhere e.g.: on menus.
- Makes camera_update_touch consistent compared to equivalent functions,
since now `pan` has now been moved to `camera` (as it should be).
The following properties are supported:
- Sound: "loop". Must be either 0 or 1
- Images: "transparent". Must be either 0 or 1
These headers are only used for non-PS1 builds, since .TIM and .VAG
files do already implement such information.
