Built SDL2_image and _mixer static

libsdl2_image/README-emscripten.txt

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+Building SDL2_image
+-------------------
+
+The easiest way to use SDL2_image with Emscripten is to use Emscripten ports (https://kripken.github.io/emscripten-site/docs/compiling/Building-Projects.html#emscripten-ports) (-s USE_SDL_IMAGE=2).
+
+If you want to build it yourself instead you can use these instructions:
+
+Step 0 - get emscripten
+
+Step 1 - get sdl2-emscripten
+ * clone https://github.com/emscripten-ports/SDL2.git
+ * follow the build instructions in SDL2/docs/README-emscripten.md (make sure to pass a --prefix to configure)
+ * make install
+
+Step 2 - get sdl_image
+ * emconfigure ./configure  --disable-sdltest --with-sdl-prefix=/path/to/sdl --prefix=/path/to/install
+ * (where /path/to/sdl is the path you passed as --prefix to SDL2 configure)
+ * emmake make
+ * make install
+