Makefile: various packaging enhancements
Created by: akien-mga
The commits should be relatively self-explanatory, they add support for:
- CFLAGS and LDFLAGS env variables used by packagers to enforce their optimisation flags, linking flags, etc.
- DESTDIR, the classical variable packagers know that they can use to define the installation target (e.g. RPM_BUILD_ROOT).
- Configurable BINDIR (for distros using
/usr/games
for game binaries) and GAMEDATADIR (for distros using/usr/share/games/<pkg>
for game data), and DATADIR for the sake of consistency (used for the man dir, and in the future we can add a desktop file, an icon, etc. in this path).