Add support for EXT_image_flush_external extension

third_party/khronos/EGL/eglext.h

Index: third_party/khronos/EGL/eglext.h
diff --git a/third_party/khronos/EGL/eglext.h b/third_party/khronos/EGL/eglext.h
index b476dc59057f578d40a78cf4f904865f3c857241..7a5433f640e4d4be9a7e41daec6c3f9697023072 100644
--- a/third_party/khronos/EGL/eglext.h
+++ b/third_party/khronos/EGL/eglext.h
@@ -574,6 +574,21 @@ typedef EGLint (EGLAPIENTRYP PFNEGLDUPNATIVEFENCEFDANDROIDPROC)(EGLDisplay dpy,
 #define EGL_SYNC_PRIOR_COMMANDS_IMPLICIT_EXTERNAL_ARM 0x328A
 #endif /* EGL_ARM_implicit_external_sync */
 
+#ifndef EGL_EXT_image_flush_external
+#define EGL_EXT_image_flush_external 1
+#ifdef EGL_EGLEXT_PROTOTYPES
+EGLAPI EGLBoolean EGLAPIENTRY
+eglImageFlushExternalEXT(EGLDisplay dpy,
+                         EGLImageKHR image,
+                         const EGLint* attrib_list);
+#else
+typedef EGLBoolean(EGLAPIENTRYP PFNGLEGLIMAGEFLUSHEXTERNALEXT)(
+    EGLDisplay dpy,
+    EGLImageKHR image,
+    const EGLint* attrib_list);
+#endif
+#endif
+
 #ifdef __cplusplus
 }
 #endif