needed for compatibility with [MSVC](https://docs.microsoft.com/en-us/cpp/c-runtime-library/math-constants?redirectedfrom=MSDN&view=msvc-160)
@@ -2,6 +2,7 @@
#define ACALC_H
#include <QDateTime>
+#define _USE_MATH_DEFINES // needed for MSVC
#include <cmath>
#include <QDebug>
/*!