[gimp] app: in polynomial_odd_roots(), fix derivative array size

[Ell <ell src gnome org>]

commit db678ad212784bc4830de60007590b6439229c7d
Author: Ell <ell_se yahoo com>
Date:   Fri Feb 7 00:54:57 2020 +0200

    app: in polynomial_odd_roots(), fix derivative array size

 app/core/gimp-transform-utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/core/gimp-transform-utils.c b/app/core/gimp-transform-utils.c
index e183807339..555ff09dbd 100644
--- a/app/core/gimp-transform-utils.c
+++ b/app/core/gimp-transform-utils.c
@@ -895,7 +895,7 @@ polynomial_odd_roots (const gdouble *poly,
     /* general case */
     default:
       {
-        gdouble deriv[degree - 1];
+        gdouble deriv[degree];
         gdouble deriv_roots[degree - 1];
         gint    n_deriv_roots;
         gdouble a;