nf.sign in 2.0.12

[Ilya Zakharevich <ilya@math.ohio-state.edu>]

Since I cannot compile 2.0.13 - neither with cc, nor with gcc - I
report a bug in 2.0.12.

? res=-23708160*x^9 - 225566208*x^8 - 1131314688*x^7 - 3968372736*x^6 - 7276863
744*x^5 - 1112932224*x^4 + 22694392512*x^3 + 49279399488*x^2 + 50845741200*x +
22483386864
%1 = -23708160*x^9 - 225566208*x^8 - 1131314688*x^7 - 3968372736*x^6 - 727686374
4*x^5 - 1112932224*x^4 + 22694392512*x^3 + 49279399488*x^2 + 50845741200*x + 224
83386864
? nf=nfinit(res);
? nf=nfinit(res);
  ***   Warning: non-monic polynomial. I shall transform it.
? nf.sign
  ***   incorrect type in .sign: nf.sign
                                    ^---

(I also got a segfault when execution the same later in a long session.)

Enjoy,
Ilya