diff --git a/simgear/scene/sky/cloud.cxx b/simgear/scene/sky/cloud.cxx
index a2b3b662..e62384b9 100644
--- a/simgear/scene/sky/cloud.cxx
+++ b/simgear/scene/sky/cloud.cxx
@@ -21,7 +21,7 @@
 // #include <stdio.h>
 #include <math.h>
 
-#if defined (__APPLE__) || defined (__FreeBSD__)
+#if defined (__APPLE__)
 // any C++ header file undefines isinf and isnan
 // so this should be included before <iostream>
 inline int (isinf)(double r) { return isinf(r); }
@@ -45,6 +45,11 @@ inline int (isnan)(double r) { return isnan(r); }
 #define isnan(x) _isnan(x)
 #endif
 
+#if defined (__FreeBSD__)
+inline int isnan(double r) { return !(r < 0 || r > 0); }
+#endif
+
+
 
 static ssgStateSelector *layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
 static bool state_initialized = false;
diff --git a/simgear/sound/soundmgr_openal.cxx b/simgear/sound/soundmgr_openal.cxx
index 1966259a..0785edb5 100644
--- a/simgear/sound/soundmgr_openal.cxx
+++ b/simgear/sound/soundmgr_openal.cxx
@@ -35,7 +35,7 @@
 # include <AL/alc.h>
 #endif
 
-#if defined (__APPLE__) 
+#if defined (__APPLE__)
 // any C++ header file undefines isinf and isnan
 // so this should be included before <iostream>
 inline int (isinf)(double r) { return isinf(r); }
@@ -46,6 +46,10 @@ inline int (isnan)(double r) { return isnan(r); }
 #define isnan(x) _isnan(x)
 #endif
 
+#if defined (__FreeBSD__)
+inline int isnan(double r) { return !(r < 0 || r > 0); }
+#endif
+
 #include STL_IOSTREAM
 
 #include <simgear/debug/logstream.hxx>