Fix #650, glIsEnabled not returning value

Author: finscn

Source/Ejecta/EJCanvas/WebGL/EJBindingCanvasContextWebGL.m

@@ -1240,7 +1240,10 @@ - (void)deleteVertexArray:(GLuint)vertexArray {
 #undef EJ_BIND_IS_OBJECT
 
 
-EJ_BIND_FUNCTION_DIRECT(isEnabled, glIsEnabled, cap);
+EJ_BIND_FUNCTION(isEnabled, ctx, argc, argv) {
+    EJ_UNPACK_ARGV(GLenum cap);
+    return JSValueMakeBoolean(ctx, glIsEnabled(cap));
+}
 
 EJ_BIND_FUNCTION(isTexture, ctx, argc, argv) {
 	if( argc < 1 ) { return NULL; }