diff --git a/src/c/num_sfun.d b/src/c/num_sfun.d
index ca562e8b1..1cfc93c04 100644
--- a/src/c/num_sfun.d
+++ b/src/c/num_sfun.d
@@ -21,13 +21,6 @@
 # undef complex
 #endif
 #include "ecl/internal.h"
-#ifndef M_PI
-# ifdef PI
-#  define M_PI PI
-# else
-#   define M_PI 3.14159265358979323846
-# endif
-#endif
 
 #ifndef HAVE_LOG1P
 double
@@ -414,19 +407,19 @@ ecl_atan2_double(double y, double x)
 		}
 	} else if (x == 0) {
 		if (y > 0) {
-			return M_PI / 2.0;
+			return ECL_PI2_D;
 		} else if (y == 0) {
 			FEerror("Logarithmic singularity.", 0);
 		} else {
-			return -M_PI / 2.0;
+			return -ECL_PI2_D;
 		}
 	} else {
 		if (y > 0) {
-			return M_PI - atan(y / -x);
+			return ECL_PI_D - atan(y / -x);
 		} else if (y == 0) {
-			return M_PI;
+			return ECL_PI_D;
 		} else {
-			return -M_PI + atan(-y / -x);
+			return -ECL_PI_D + atan(-y / -x);
 		}
 	}
 }
@@ -445,19 +438,19 @@ ecl_atan2_long_double(long double y, long double x)
 		}
 	} else if (x == 0) {
 		if (y > 0) {
-			return M_PI / 2.0;
+			return ECL_PI2_L;
 		} else if (y == 0) {
 			FEerror("Logarithmic singularity.", 0);
 		} else {
-			return -M_PI / 2.0;
+			return -ECL_PI2_L;
 		}
 	} else {
 		if (y > 0) {
-			return M_PI - atanl(y / -x);
+			return ECL_PI_L - atanl(y / -x);
 		} else if (y == 0) {
-			return M_PI;
+			return ECL_PI_L;
 		} else {
-			return -M_PI + atanl(-y / -x);
+			return -ECL_PI_L + atanl(-y / -x);
 		}
 	}
 }
diff --git a/src/c/number.d b/src/c/number.d
index 087a116aa..558fa0e5a 100644
--- a/src/c/number.d
+++ b/src/c/number.d
@@ -16,22 +16,13 @@
 */
 
 #include <ecl/ecl.h>
-#include <math.h>
 #include <float.h>
+#include <math.h>
 #ifdef _MSC_VER
 # undef complex
 #endif
-#include <float.h>
 #include <ecl/internal.h>
 
-#ifndef M_PI
-# ifdef PI
-#  define M_PI PI
-# else
-#   define M_PI 3.14159265358979323846
-# endif
-#endif
-
 cl_fixnum
 fixint(cl_object x)
 {
@@ -604,9 +595,9 @@ init_number(void)
 	    ecl_make_complex(ecl_make_singlefloat(0.0), ecl_make_singlefloat(2.0));
 
 #ifdef ECL_LONG_FLOAT
-	ECL_SET(@'pi', make_longfloat(M_PI));
+	ECL_SET(@'pi', make_longfloat((long double)ECL_PI_L));
 #else
-	ECL_SET(@'pi', ecl_make_doublefloat(M_PI));
+	ECL_SET(@'pi', ecl_make_doublefloat((double)ECL_PI_D));
 #endif
 
 	init_big();
diff --git a/src/h/internal.h b/src/h/internal.h
index d81cd09ae..ad1cfe034 100644
--- a/src/h/internal.h
+++ b/src/h/internal.h
@@ -216,6 +216,11 @@ typedef int fenv_t;
 # define fesetenv(bits) _controlfp(*(bits), MCW_EM)
 #endif
 
+#define ECL_PI_D 3.14159265358979323846264338327950288
+#define ECL_PI_L 3.14159265358979323846264338327950288l
+#define ECL_PI2_D 1.57079632679489661923132169163975144
+#define ECL_PI2_L 1.57079632679489661923132169163975144l
+
 /*
  * Fake several ISO C99 mathematical functions
  */