Add documentation for package maintainers

README.md

@@ -162,10 +162,8 @@ is searched at:
 - The directory given with the *+set basedir /path/to/quake2_installation/*
   commandline argument.
 
-Yamagi Quake II has support for an alternative startup config. It may be a good
+If you're a package maintainer, please look at our documentation at
-idea to install it, since it sets some global options to sane defaults. Copy
+[stuff/packaging.md](stuff/packaging.md).
-yq2.cfg to the baseq2/ subdirectory in your gamedata directory. Usually yq2.cfg
-can be found somewhere in /usr/share or /usr/local/share.
 
 
 ### Compiling from source

stuff/packaging.md

@@ -0,0 +1,66 @@
+# Notes for Package Maintainers
+
+Our 7.00 release caused some trouble for package maintainers
+(see https://github.com/yquake2/yquake2/issues/214), so we decided to finally
+properly document how we think it should be done and what assumptions
+Yamagi Quake II makes regarding binary locations etc.
+
+## Where you should put the executables
+
+Yamagi Quake II expects all binaries (executables and libs) to be in the same directory
+(or, in the case of game.so/.dll/dylib, in the mod-specific subdirectory).
+
+So the binary directory should look somehow like this *(on Unix-like systems;
+on Windows and OSX it's very similar but with different extensions: .dll or 
+.dylib instead of .so, and the executables have .exe file extension on Windows of course)*:
+
+* /path/to/yamagi-quake2/
+  - quake2
+  - q2ded
+  - ref_gl1.so
+  - ref_gl3.so
+  - baseq2/
+    * game.so
+  - xatrix/
+    * game.so
+  - ... *(the same for other addons/mods)*
+
+Yamagi Quake2 will get the directory the `quake2` executable is in from the system
+and then look in that directory (and nowhere else!) for `ref_*.so`.  
+It will look for `game.so` there first, but if it's not found in the binary directory,
+it will look for it in all directories that are also searched for game
+data (SYSTEMDIR, basedir, $HOME/.yq2/). This is for better compatibility with mods that
+might ship their own game.so.
+
+You can **just symlink the executables to a directory in your $PATH**, like /usr/bin/.  
+(*Except on OpenBSD, which does not provide a way to get the executable directory,
+ there you'll need a shellscript that first does a `cd /path/to/yamagi-quake2/` and
+ then executes `./quake2`*)
+
+We want all binaries to be in the same directory to ensure that people don't accidentally
+update only parts of their Yamagi Quake II installtion, so they'd end up with a new
+quake2 executable and old render libraries (`ref_*.so`) and report weird bugs.
+
+## The SYSTEMWIDE and SYSTEMDIR options
+
+The Makefile allows you to enable the `SYSTEMWIDE` feature (`WITH_SYSTEMWIDE=yes`) and
+lets you specify the directory that will be used (`SYSTEMDIR`, `WITH_SYSTEMDIR=/your/custom/path/`).
+If you don't set SYSTEMDIR, it defaults to `/usr/share/games/quake2`, which is what debian uses.
+
+The `SYSTEMDIR` was meant to contain just the game data, *not* the binaries, and allows
+several Quake2 source ports to share the same game data.  
+Unfortunately, we didn't document this assumption, so some packages used it for both binaries
+and data, just binaries or - which causes most trouble - only for the game libs, but not the
+executables. The latter case doesn't work anymore since we (re)introduced the render libs,
+as they need to be located next to the executable, and if the executable is in /usr/bin/ you
+don't want to put libs next to it.
+
+Anyway: If you use `SYSTEMWIDE`/`SYSTEMDIR`, please use it for game data.  
+You *can* also put the binaries in there, but in that case please put all of them
+(including executables) in there, as explained above.
+
+## Alternative startup config
+
+Yamagi Quake II has support for an alternative startup config.  
+It may be a good idea to install it, since it sets some global options to sane defaults.  
+Copy yq2.cfg to the baseq2/ subdirectory in the gamedata (`SYSTEMDIR`) directory.