egl/display: workaround gbm platforms on EGL 1.4

Some EGL drivers report the KHR extension with EGL 1.4, which doesn't
make any sense, however given that the constant for MESA and KHR is the
same, we can check for KHR in MESA branch, but still use the Ext
functions.

Fixes #1708.

CHANGELOG.md

@@ -10,6 +10,7 @@
 - Added `NotCurrentContext::make_current_surfaceless(self)` and
   `PossiblyCurrentContext::make_current_surfaceless(&self)` in the `Wgl`
   implementation to allow the use of surfaceless contexts with WGL.
+- Added workaround for EGL drivers reporting KHR_platform_gbm with EGL 1.4.
 
 
 # Version 0.32.1

glutin/src/api/egl/display.rs

@@ -362,7 +362,18 @@ impl Display {
                     handle.connection.map_or(egl::DEFAULT_DISPLAY as *mut _, |c| c.as_ptr()),
                 )
             },
-            RawDisplayHandle::Gbm(handle) if extensions.contains("EGL_MESA_platform_gbm") => {
+            RawDisplayHandle::Gbm(handle)
+                // NOTE: Some drivers report that they support KHR extension with 1.4 EGL display, so
+                // workaround here by checking the KHR gbm display as well. The MESA and KHR has
+                // the same constant values, thus it'll work regardless.
+                //
+                // They do require EXT during the runtime as well, so we don't change the display
+                // to Khr here.
+                //
+                // See https://github.com/rust-windowing/glutin/issues/1708.
+                if extensions.contains("EGL_MESA_platform_gbm")
+                    || extensions.contains("EGL_KHR_platform_gbm") =>
+            {
                 (egl::PLATFORM_GBM_MESA, handle.gbm_device.as_ptr())
             },
             RawDisplayHandle::Drm(_) => {