diff --git a/src/QGC.h b/src/QGC.h
index bf36900d332a8dd1365ead9e14eacd0d1ebbb35f..e49b2a4ce76c27b6452519d64740fc0466f6c634 100644
--- a/src/QGC.h
+++ b/src/QGC.h
@@ -49,7 +49,7 @@ inline bool isinf(T value)
 {
     return (value == std::numeric_limits<T>::infinity() || (-1*value) == std::numeric_limits<T>::infinity()) && std::numeric_limits<T>::has_infinity;
 }
-#else
+#elif defined __APPLE__
 #include <cmath>
 #ifndef isnan
 #define isnan(x) std::isnan(x)