Restore support for the Nokia N-Gage (#12148)

docs/README-ngage.md

@@ -1,5 +1,64 @@
-Support for the Nokia N-Gage has been removed from SDL3 (but will make a
-comeback when newer compilers are available for the platform).
+# Nokia N-Gage
 
-SDL2 still supports this platform.
+SDL port for the Nokia N-Gage
+[Homebrew toolchain](https://github.com/ngagesdk/ngage-toolchain)
+contributed by:
 
+- [Michael Fitzmayer](https://github.com/mupfdev)
+
+- [Anonymous Maarten](https://github.com/madebr)
+
+Many thanks to:
+
+- icculus and slouken for always making room for us <20> even when we show up in 2025
+ still waving the N-Gage flag.
+
+- The Nokia N-Gage [Discord community](https://discord.gg/dbUzqJ26vs)
+ who keeps the platform alive.
+
+- The staff and supporters of the
+ [Suomen pelimuseo](https://www.vapriikki.fi/nayttelyt/fantastinen-floppi/), and
+ to Heikki Jungmann, for their ongoing love and dedication for the Nokia N-Gage <20> you
+ guys are awesome!
+ 
+## History
+
+When SDL support was discontinued due to the lack of C99 support at the time,
+this version was rebuilt from the ground up after resolving the compiler issues.
+
+In contrast to the earlier SDL2 port, this version features a dedicated rendering
+backend and a functional, albeit limited, audio interface.  Support for the
+software renderer has been removed.
+
+The outcome is a significantly leaner and more efficient SDL port, which we hope
+will breathe new life into this beloved yet obscure platform.
+
+## To the Stubborn Legends of the DC Scene  
+
+This port is lovingly dedicated to the ever-nostalgic Dreamcast homebrew scene <20>
+because if we managed to pull this off for the N-Gage (yes, the N-Gage), surely
+you guys can stop clinging to SDL2 like it's a rare Shenmue prototype and finally
+make the leap to SDL3.  It<49>s 2025, not 1999 <20> and let<65>s be honest, you<6F>re rocking
+a state-of-the-art C23 compiler.  The irony writes itself.
+
+## Existing Issues and Limitations
+
+- For now, the new
+ [SDL3 main callbacks](https://wiki.libsdl.org/SDL3/README/main-functions#how-to-use-main-callbacks-in-sdl3)
+ are not optional and must be used. This is important as the callbacks
+ are optional on other platforms.
+
+- If the application is put in the background while sound is playing,
+ some of the audio is looped until the app is back in focus.
+
+- It is recommended initialising SDLs audio sub-system even when it
+ is not required. The backend is started at a higher level.  Initialising
+ SDLs audio sub-system ensures that the backend is properly deinitialised.
+
+- Because the audio sample rate can change during phone calls, the sample
+ rate is currently fixed at 8kHz to ensure stable behavior.  Although
+ dynamically adjusting the sample rate is theoretically possible, the
+ current implementation doesn't support it yet.  This limitation is
+ expected to be resolved in a future update.
+
+- Dependency tracking is currently non-functional.