src/sage/rings/polynomial/polynomial_ring.py: Use '# needs sage.libs.ntl' when GF2X is used

Author: Matthias Koeppe

src/sage/rings/function_field/order_rational.py

@@ -273,7 +273,7 @@ def _residue_field_global(self, q, name=None):
             sage: k.<a> = GF(2)                                                                     # optional - sage.rings.finite_rings
             sage: F.<x> = FunctionField(k)                                                          # optional - sage.rings.finite_rings
             sage: O = F.maximal_order()                                                             # optional - sage.rings.finite_rings
-            sage: O._ring                                                                           # optional - sage.rings.finite_rings
+            sage: O._ring                                                                           # optional - sage.rings.finite_rings sage.libs.ntl
             Univariate Polynomial Ring in x over Finite Field of size 2 (using GF2X)
             sage: f = x^3 + x + 1                                                                   # optional - sage.rings.finite_rings
             sage: _f = f.numerator()                                                                # optional - sage.rings.finite_rings