diff --git a/intern/audaspace/intern/AUD_ChannelMapperReader.cpp b/intern/audaspace/intern/AUD_ChannelMapperReader.cpp
index dd6f5b43953..27d10ce6dc8 100644
--- a/intern/audaspace/intern/AUD_ChannelMapperReader.cpp
+++ b/intern/audaspace/intern/AUD_ChannelMapperReader.cpp
@@ -60,7 +60,7 @@ void AUD_ChannelMapperReader::setChannels(AUD_Channels channels)
 
 void AUD_ChannelMapperReader::setMonoAngle(float angle)
 {
-	if(std::isnan(angle))
+	if(angle != angle)
 		angle = 0;
 	m_mono_angle = angle;
 	if(m_source_channels == AUD_CHANNELS_MONO)
diff --git a/intern/audaspace/intern/AUD_SoftwareDevice.cpp b/intern/audaspace/intern/AUD_SoftwareDevice.cpp
index 5e430860704..125b9d705dd 100644
--- a/intern/audaspace/intern/AUD_SoftwareDevice.cpp
+++ b/intern/audaspace/intern/AUD_SoftwareDevice.cpp
@@ -43,6 +43,10 @@
 #include <cmath>
 #include <limits>
 
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
 typedef enum
 {
 	AUD_RENDER_DISTANCE = 0x01,