Fix not linking against OpenGLES.framework for iOS (rust-windowing#1224)

Author: Aleksi Juvani

README.md

@@ -81,10 +81,6 @@ The plan is that glutin tries to dynamically link-to and use wayland if possible
 
 Due to an issue with how mesa and Wayland play together, all shared contexts must use the same events pool as each other.
 
-### iOS
-
-In order to build in XCode, you must link both `UIKit.framework` and `OpenGLES.framework`. In order for your app to not crash while attempting to obtain a context, you must also link `CoreFoundation.framework` and `GLKit.framework`.
-
 ## Common issues
 
 Help! I'm receiving `NoAvailablePixelFormat`!

glutin_gles2_sys/build.rs

@@ -10,6 +10,8 @@ fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
     if target.contains("ios") {
+        println!("cargo:rustc-link-lib=framework=GLKit");
+        println!("cargo:rustc-link-lib=framework=OpenGLES");
         let mut file = File::create(&dest.join("gles2_bindings.rs")).unwrap();
         Registry::new(Api::Gles2, (2, 0), Profile::Core, Fallbacks::None, [])
             .write_bindings(gl_generator::StaticStructGenerator, &mut file)

glutin_gles2_sys/src/lib.rs

@@ -79,9 +79,6 @@ pub const kEAGLRenderingAPIOpenGLES1: NSUInteger = 1;
 pub const kEAGLRenderingAPIOpenGLES2: NSUInteger = 2;
 pub const kEAGLRenderingAPIOpenGLES3: NSUInteger = 3;
 
-#[link(name = "UIKit", kind = "framework")]
-#[link(name = "CoreFoundation", kind = "framework")]
-#[link(name = "GlKit", kind = "framework")]
 extern "C" {
     pub static kEAGLColorFormatRGB565: id;
     // pub static kEAGLColorFormatRGBA8: id;