diff --git a/src/platform.h b/src/platform.h
index fba2078bb..97d254e2d 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -48,4 +48,10 @@ char * strdup(const char *s);
 int mkdir(const char *pathname, int mode);
 #endif
 
+/* do not use M_PI, use one of these instead: */
+#define PI_F 3.1415926535897932384626433832795F
+#define PI_D 3.1415926535897932384626433832795
+#define PI_L 3.1415926535897932384626433832795L
+
+
 #endif
diff --git a/src/util/rand.c b/src/util/rand.c
index bd8543b9e..441461068 100644
--- a/src/util/rand.c
+++ b/src/util/rand.c
@@ -28,8 +28,6 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <float.h>
 #include <ctype.h>
 
-#define PI_L 3.1415926535897932384626433832795L
-
 int lovar(double xpct_x2)
 {
     int n = (int)(xpct_x2 * 500) + 1;
@@ -51,10 +49,10 @@ double normalvariate(double mu, double sigma)
     if (phase == 0) {
         U = (rng_int() + 1.) / (RNG_RAND_MAX + 2.);
         V = rng_int() / (RNG_RAND_MAX + 1.);
-        Z = sqrt(-2 * log(U)) * sin(2 * PI_L * V);
+        Z = sqrt(-2 * log(U)) * sin(2 * PI_D * V);
     }
     else {
-        Z = sqrt(-2 * log(U)) * cos(2 * PI_L * V);
+        Z = sqrt(-2 * log(U)) * cos(2 * PI_D * V);
     }
     phase = 1 - phase;