Corrected minor issues with steamshim and documented the building

steamshim/steamshim_child.c

@@ -28,7 +28,9 @@ typedef int PipeType;
 #ifdef STEAMSHIM_DEBUG
 #define dbgpipe printf
 #else
-static inline void dbgpipe(const char *fmt, ...) {}
+static inline void dbgpipe(const char *fmt, ...) {
+    (void)fmt;
+}
 #endif
 
 static int writePipe(PipeType fd, const void *buf, const unsigned int _len);

steamshim_parent/Makefile

@@ -20,7 +20,7 @@ FLAGS			+= -lsteam_api
 
 ifeq ($(DEBUG),1)
 	FLAGS		+= -DSTEAMSHIM_DEBUG
-else
+else ifeq ($(HOST),w32)
 	FLAGS		+= -mwindows
 endif
 

steamshim_parent/README.md

@@ -0,0 +1,22 @@
+# Steamshim parent
+OneShot uses [steamshim](https://hg.icculus.org/icculus/steamshim/) for GNU GPL v3 and Steam interoperability. There are five components that OneShot uses to communicate with Steam, in order:
+1. Steamworks SDK (that can be obtained from [here](https://partner.steamgames.com)) that is used for directly communicating with Steam. It is closed-source, and because of license compatibility issues steamshim must be used as a layer between OneShot and Steamworks SDK to communicate with Steam.
+2. steamshim parent (whose source is within this folder) is a separate application that will start up the main OneShot application and can communicate with the Steamworks SDK.
+3. steamshim child (whose source is inside the `steamshim` folder) is the client used to communicate with the steamshim parent from the OneShot application through pipes.
+4. Steam controller inside OneShot application (`src/steam.cpp`) controls the communication between OneShot and steamshim components.
+5. Steam binding (`binding-mri/steam-binding.cpp`) creates Ruby objects so Steam functionalities (like achievements) can be controlled from the game's scripts/events and passes on the handling to the Steam controller
+
+## Building
+Download Steamworks SDK from [here](https://partner.steamgames.com) and run
+```console
+$ export LD_LIBRARY_PATH=/path/to/steamworks/sdk/redistributable_bin/platform
+$ STEAMWORKS=/path/to/steamworks/sdk HOST=platform make
+```
+inside this directory, where `platform` can be `win64`, `osx32`, `linux64` or `linux32`
+
+If you need debug output from the steamshim parent, compile with `DEBUG=1` in command-line arguments for `make`.
+
+## Running
+After building the steamshim parent, place it in the same directory as the OneShot application. Note that the OneShot application **must be named "oneshot"**. Changing the case ("OneShot") will make the game not launch.
+
+To run the game with the Steam wrapper, run the steamshim parent.

steamshim_parent/steamshim_parent.cpp

@@ -30,7 +30,9 @@ typedef int PipeType;
 #ifdef STEAMSHIM_DEBUG
 #define dbgpipe printf
 #else
-static inline void dbgpipe(const char *fmt, ...) {}
+static inline void dbgpipe(const char *fmt, ...) {
+    (void)fmt;
+}
 #endif
 
 /* platform-specific mainline calls this. */
@@ -245,6 +247,7 @@ static bool launchChild(ProcessType *pid)
 
     // we're the child.
     GArgv[0] = strdup("./" GAME_LAUNCH_NAME);
+    dbgpipe("Starting %s\n", GArgv[0]);
     execvp(GArgv[0], GArgv);
     // still here? It failed! Terminate, closing child's ends of the pipes.
     _exit(1);