Add note about required libraries on Linux

Closes https://github.com/emilk/egui/issues/121

README.md

@@ -38,7 +38,9 @@ If you have questions, use [Discussions](https://github.com/emilk/egui/discussio
 
 [Click to run egui web demo](https://emilk.github.io/egui/index.html).
 
-[Hobogo](https://emilk.github.io/hobogo/index.html): A small game I made using egui. Source: <https://github.com/emilk/hobogo>
+To test the demo app locally, run `cargo run --release -p egui_demo_app`.
+
+On Linux you need to first run `sudo apt-get install libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev`.
 
 ### Example
 

eframe/README.md

@@ -5,3 +5,5 @@ This aims to be the entry-level crate if you want to write an egui app.
 `eframe` calls into your code (it is a framework) and supports web apps (via [`egui_web`](https://crates.io/crates/egui_web)) and native apps (via [`egui_glium`](https://crates.io/crates/egui_glium)).
 
 `eframe` is a very thin crate that re-exports [`egui`](https://crates.io/crates/egui), [`epi`](https://crates.io/crates/epi) and thin wrappers over the backends.
+
+On Linux you need to first run `sudo apt-get install libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev` to compile `eframe` natively.

egui_glium/README.md

@@ -6,3 +6,5 @@
 # egui_glium
 
 This crates provides bindings between [egui](https://crates.io/crates/egui) and [glium](https://crates.io/crates/glium) which allows you to write GUI code using egui and compile it and run it natively, cross platform.
+
+For linux you need to `sudo apt-get install libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev` to use `egui_glium`.