New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/base/fast_math.cpp

@@ -0,0 +1,19 @@
+// Separate cpp for different compiler flags.
+#include <cmath>
+#include <limits>
+
+namespace math
+{
+double Nan()
+{
+  return std::numeric_limits<double>::quiet_NaN();
+}
+double Infinity()
+{
+  return std::numeric_limits<double>::infinity();
+}
+bool is_finite(double t)
+{
+  return std::isfinite(t);
+}
+} // namespace base