Changed M_LN10 to std::numbers::ln10

src/Info.cc

@@ -13,6 +13,7 @@
 */
 
 #include <cdi.h>
+#include <numbers>
 
 #include "cdo_task.h"
 #include "cdo_options.h"
@@ -79,7 +80,7 @@ compute_level(double min, double max, double (&level)[10])
 
   if (is_not_equal(step, 0.0))
     {
-      auto a = std::pow(10.0, std::floor(std::log(step) / M_LN10));
+      auto a = std::pow(10.0, std::floor(std::log(step) / std::numbers::ln10));
       auto b = step / a;
 
       // clang-format off

src/const.h

@@ -15,10 +15,6 @@ constexpr double MAX_T = 400.;
 constexpr double MIN_Q = 0.0;
 constexpr double MAX_Q = 0.1;
 
-#ifndef M_LN10
-#define M_LN10 2.30258509299404568401799145468436421 /* log_e 10 */
-#endif
-
 #ifndef M_PI
 #define M_PI 3.14159265358979323846264338327950288 /* pi */
 #endif