# As C standards does not define M_PI or M_PI_2 provide a fallback
# bug 907442
diff --git a/src/muf.c b/src/muf.c
index 6671651..1f880fd 100644
--- a/src/muf.c
+++ b/src/muf.c
@@ -32,6 +32,10 @@
 #include "tlf_panel.h"
 #include "ui_utils.h"
 
+#ifndef M_PI_2
+	# define M_PI_2         1.57079632679489661923  /* pi/2 */
+#endif
+
 
 // message splitters:
 // line[0] - original line, content can be modified in-place
diff --git a/src/qrb.h b/src/qrb.h
index 89d3f30..0120de0 100644
--- a/src/qrb.h
+++ b/src/qrb.h
@@ -21,6 +21,10 @@
 #ifndef QRB_H
 #define QRB_H
 
+#ifndef M_PI
+	# define M_PI           3.14159265358979323846  /* pi */
+#endif
+
 #define ARC_IN_KM 111.2
 #define RADIAN  (180.0 / M_PI)
 
diff --git a/src/sunup.c b/src/sunup.c
index b1186dd..7412c06 100644
--- a/src/sunup.c
+++ b/src/sunup.c
@@ -23,6 +23,10 @@
 
 #include "get_time.h"
 
+#ifndef M_PI
+        # define M_PI           3.14159265358979323846  /* pi */
+#endif
+
 #define RADIAN  (180.0 / M_PI)