Fix compilation issue due on debian 9 stretch

src/libmath.c

@@ -25,7 +25,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 static double inv(double a)
 {
 double v;
-   if (a==0.0) v=HUGE;
+   if (a==0.0) v=HUGE_VAL;
    else v = (double)1.0/a;
    return v;
 }