update changelog and readme

CHANGELOG.md

@@ -1,5 +1,13 @@
 ## Updates
 
+- **25-Sep-2022**: sokol_app.h on Linux now optionally supports EGL instead of 
+  GLX for the window system glue code and can create a GLES2 or GLES3 context
+  instead of a 'desktop GL' context. 
+  To get EGL+GLES2/GLES3, just define SOKOL_GLES2 or SOKOL_GLES3 to compile the
+  implementation. To get EGL+GL, define SOKOL_GLCORE33 *and* SOKOL_FORCE_EGL.
+  By default, defining just SOKOL_GLCORE33 uses GLX for the window system glue
+  (just as before).
+
 - **10-Sep-2022**: sokol_app.h and sokol_args.h has been fixed for Emscripten 3.21, those headers
   used the Emscripten Javascript helper function ```ccall()``` which is now part of the
   'legacy runtime' and causes linker errors. Instead of ```ccall()``` sokol_app.h and sokol_args.h

README.md

@@ -4,7 +4,8 @@ Simple
 [STB-style](https://github.com/nothings/stb/blob/master/docs/stb_howto.txt)
 cross-platform libraries for C and C++, written in C.
 
-[**See what's new**](https://github.com/floooh/sokol/blob/master/CHANGELOG.md) (**10-Sep-2022** an important compatibility fix for Emscripten 3.21 in sokol_app.h and sokol_args.h)
+[**See what's new**](https://github.com/floooh/sokol/blob/master/CHANGELOG.md) (**25-Sep-2022** sokol_app.h: EGL/GLES2/GLES3
+support on Linux)
 
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