$NetBSD: patch-simgear_sound_sample__group_cxx,v 1.1 2012/09/30 01:50:16 dholland Exp $

Fix build failure on NetBSD.

--- simgear/sound/sample_group.cxx~	2012-08-16 14:20:28.000000000 +0000
+++ simgear/sound/sample_group.cxx
@@ -22,2 +22,4 @@
 
+#include <cmath>
+
 #ifdef HAVE_CONFIG_H
@@ -32,3 +34,3 @@
 bool isNaN(float *v) {
-   return (isnan(v[0]) || isnan(v[1]) || isnan(v[2]));
+   return (std::isnan(v[0]) || std::isnan(v[1]) || std::isnan(v[2]));
 }
