Added INTRO-emscripten.md

docs/INTRO-emscripten.md

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+
+# Introduction to SDL with Emscripten
+
+First, you should have the Emscripten SDK installed from:
+
+https://emscripten.org/docs/getting_started/downloads.html
+
+We'll start by creating a simple project to build and run [hello.c](hello.c)
+
+## Building SDL
+
+Once you have a command line interface with the Emscripten SDK set up and you've changed directory to the SDL directory, you can build SDL like this:
+
+```sh
+mkdir hello
+cd hello
+emcmake cmake ..
+emmake make
+```
+
+## Building your app
+
+In this case we'll just run a simple command to compile our source with the SDL library we just built:
+```sh
+emcc -o index.html ../docs/hello.c -I../include -L. -lSDL3
+```
+
+## Running your app
+
+You can now run your app by pointing a webserver at your build directory and connecting a web browser to it.
+
+## More information
+
+A more complete example is available at:
+
+https://github.com/Ravbug/sdl3-sample
+
+Additional information and troubleshooting is available in [README-emscripten.md](README-emscripten.md)