make return type of supported_extensions based on feature

src/lib.rs

@@ -16,6 +16,9 @@ compile_error!("\"hashbrown\" feature should be enabled in \"no_std\" environmen
 
 use alloc::{boxed::Box, string::String, vec::Vec};
 use core::{fmt::Debug, hash::Hash};
+
+#[cfg(not(feature = "std"))]
+use hashbrown::HashSet;
 #[cfg(feature = "std")]
 use std::collections::HashSet;
 
@@ -163,8 +166,12 @@ pub trait HasContext: __private::Sealed {
     type TransformFeedback: Copy + Clone + Debug + Eq + Hash + Ord + PartialEq + PartialOrd;
     type UniformLocation: Clone + Debug;
 
+    #[cfg(feature = "std")]
     fn supported_extensions(&self) -> &HashSet<String>;
 
+    #[cfg(not(feature = "std"))]
+    fn supports_extension(&self) -> Vec<String>;
+
     fn supports_debug(&self) -> bool;
 
     fn version(&self) -> &Version;

src/native.rs

@@ -201,10 +201,16 @@ impl HasContext for Context {
     type UniformLocation = NativeUniformLocation;
     type TransformFeedback = NativeTransformFeedback;
 
+    #[cfg(feature = "std")]
     fn supported_extensions(&self) -> &HashSet<String> {
         &self.extensions
     }
 
+    #[cfg(not(feature = "std"))]
+    fn supports_extension(&self) -> Vec<String> {
+        self.extensions.iter().map(|v| v.clone()).collect()
+    }
+
     fn supports_debug(&self) -> bool {
         if self.extensions.contains("GL_KHR_debug") {
             // Supports extension (either GL or GL ES)

src/web_sys.rs

@@ -1606,8 +1606,14 @@ impl HasContext for Context {
     type UniformLocation = WebGlUniformLocation;
     type TransformFeedback = WebTransformFeedbackKey;
 
+    #[cfg(feature = "std")]
     fn supported_extensions(&self) -> &HashSet<String> {
-        &self.supported_extensions
+        &self.extensions
+    }
+
+    #[cfg(not(feature = "std"))]
+    fn supports_extension(&self) -> Vec<String> {
+        self.extensions.iter().map(|v| v.clone()).collect()
     }
 
     fn supports_debug(&self) -> bool {