Aniso Fix Webgl1

src/Shaders/pbr.fragment.fx

@@ -1,4 +1,4 @@
-#if defined(BUMP) || !defined(NORMAL) || defined(FORCENORMALFORWARD) || defined(SPECULARAA) || defined(CLEARCOAT_BUMP)
+#if defined(BUMP) || !defined(NORMAL) || defined(FORCENORMALFORWARD) || defined(SPECULARAA) || defined(CLEARCOAT_BUMP) || defined(ANISOTROPIC)
 #extension GL_OES_standard_derivatives : enable
 #endif