Adding '#define _USE_MATH_DEFINES' to make M_PI declared in Intel and MSVC compilers (#3238)

Co-authored-by: Paul Romano <[email protected]>

Author: MAS-OUD

src/external/quartic_solver.cpp

@@ -1,4 +1,5 @@
 #include <algorithm>
+#define _USE_MATH_DEFINES // to make M_PI declared in Intel and MSVC compilers
 #include <cmath>
 #include <complex>
 #include <cstdlib>

src/mesh.cpp

@@ -1,7 +1,8 @@
 #include "openmc/mesh.h"
-#include <algorithm> // for copy, equal, min, min_element
-#include <cmath>     // for ceil
-#include <cstddef>   // for size_t
+#include <algorithm>      // for copy, equal, min, min_element
+#define _USE_MATH_DEFINES // to make M_PI declared in Intel and MSVC compilers
+#include <cmath>          // for ceil
+#include <cstddef>        // for size_t
 #include <gsl/gsl-lite.hpp>
 #include <string>
 

src/plot.cpp

@@ -1,6 +1,8 @@
 #include "openmc/plot.h"
 
 #include <algorithm>
+#define _USE_MATH_DEFINES // to make M_PI declared in Intel and MSVC compilers
+#include <cmath>
 #include <cstdio>
 #include <fstream>
 #include <sstream>