group: add gej_eq_var

src/group.h

@@ -97,6 +97,9 @@ static void secp256k1_gej_set_infinity(secp256k1_gej *r);
 /** Set a group element (jacobian) equal to another which is given in affine coordinates. */
 static void secp256k1_gej_set_ge(secp256k1_gej *r, const secp256k1_ge *a);
 
+/** Check two group elements (jacobian) for equality in variable time. */
+static int secp256k1_gej_eq_var(const secp256k1_gej *a, const secp256k1_gej *b);
+
 /** Compare the X coordinate of a group element (jacobian). */
 static int secp256k1_gej_eq_x_var(const secp256k1_fe *x, const secp256k1_gej *a);