Only add glutin dependency if you are using the glow backend (#2402)

crates/eframe/Cargo.toml

@@ -35,7 +35,7 @@ dark-light = ["dep:dark-light"]
 default_fonts = ["egui/default_fonts"]
 
 ## Use [`glow`](https://github.com/grovesNL/glow) for painting, via [`egui_glow`](https://github.com/emilk/egui/tree/master/crates/egui_glow).
-glow = ["dep:glow", "egui_glow"]
+glow = ["dep:glow", "dep:egui_glow", "dep:glutin"]
 
 ## Enable saving app state to disk.
 persistence = [
@@ -87,15 +87,6 @@ egui-winit = { version = "0.19.0", path = "../egui-winit", default-features = fa
   "clipboard",
   "links",
 ] }
-# we can expose these to user so that they can select which backends they want to enable to avoid compiling useless deps.
-# this can be done at the same time we expose x11/wayland features of winit crate.
-glutin = { version = "0.30.0", features = [
-  "egl",
-  "glx",
-  "x11",
-  "wayland",
-  "wgl",
-] }
 raw-window-handle = { version = "0.5.0" }
 winit = "0.27.2"
 
@@ -105,6 +96,17 @@ directories-next = { version = "2", optional = true }
 egui-wgpu = { version = "0.19.0", path = "../egui-wgpu", optional = true, features = [
   "winit",
 ] } # if wgpu is used, use it with winit
+
+# we can expose these to user so that they can select which backends they want to enable to avoid compiling useless deps.
+# this can be done at the same time we expose x11/wayland features of winit crate.
+glutin = { version = "0.30.0", optional = true, es = [
+  "egl",
+  "glx",
+  "x11",
+  "wayland",
+  "wgl",
+] }
+
 image = { version = "0.24", optional = true, default-features = false, features = [
   "png",
 ] }