Add constants file to avoid issues on macOS with M_PIl not being defined

Author: rpep

native/include/c_constants.h

@@ -0,0 +1,11 @@
+#pragma once
+
+// GNU compilers on Linux should already have this defined
+#ifndef M_PIl
+#define M_PIl 3.141592653589793238462643383279
+#endif
+
+#define MU_0 (4*M_PIl*1e-7)
+#define MU_0_INV (1/MU_0)
+
+

native/src/a_random.cpp

@@ -2,6 +2,7 @@
 #include <time.h>
 #include <math.h>
 #include "a_random.h"
+#include "c_constants.h"
 
 mt19937_state *create_mt19937_state(void) {
 

native/src/a_util.cpp

@@ -2,6 +2,7 @@
 #include "c_vectormath.h"
 #include<complex>
 #include<cmath>
+#include "c_constants.h"
 
 using namespace std::complex_literals;
 

native/src/c_demag_oommf.cpp

@@ -44,7 +44,7 @@ to copyright protection within the United States.
 #include <stdlib.h>
 #include "c_dipolar.h"
 #include "c_demagcoef.h"
-
+#include "c_constants.h"
 
 int AS_Compare(const void* px,const void* py) {
   // Comparison based on absolute values

native/src/c_nebm_spherical_lib.cpp

@@ -1,6 +1,7 @@
 #include "c_nebm_spherical_lib.h"
 #include "c_nebm_lib.h"
 #include "math.h"
+#include "c_constants.h"
 
 double compute_norm_spherical(double * a, int n, int scale) {
     /* Compute the norm of an array *a. *a is assumed to have spherical

native/src/c_tensor_2dpbc.cpp

@@ -3,6 +3,7 @@
 #include "c_dipolar.h"
 #include "c_demagcoef.h"
 #include "c_tensor_2dpbc.h"
+#include "c_constants.h"
 
 double DemagTensorNormal(enum Type_Nij comp,double x,double y,double z,double a,double b,double c)
 {

native/src/m_util.cpp

@@ -1,6 +1,6 @@
 #include "m_clib.h"
 #include "c_vectormath.h"
-
+#include "c_constants.h"
 
 // Compute: S \cdot (S_i \times S_j)
 inline double volume(double S[3], double Si[3], double Sj[3]) {