2 files changed, 8 insertions, 0 deletions
diff --git a/lib/os.h b/lib/os.h
index 9ded7358..f0947dc9 100644
--- a/lib/os.h
+++ b/lib/os.h
@@ -20,6 +20,10 @@
 #include "config.h"
 #endif
 
+#ifdef _MSC_VER
+#define _USE_MATH_DEFINES
+#endif
+
 #include <math.h>
 #include <ogg/os_types.h>
 
diff --git a/test/util.c b/test/util.c
index 3dc1597c..1eb95e13 100644
--- a/test/util.c
+++ b/test/util.c
@@ -14,6 +14,10 @@
 
  ********************************************************************/
 
+#ifdef _MSC_VER
+#define _USE_MATH_DEFINES
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>