Fix build under certain systems

Fixes #530

source/modules/water/maths/MathsFunctions.h

@@ -31,6 +31,7 @@
 #include "CarlaUtils.hpp"
 
 #include <algorithm>
+#include <cmath>
 
 namespace water {
 

source/modules/water/text/String.h

@@ -29,6 +29,8 @@
 #include "CharPointer_UTF8.h"
 #include "../memory/Memory.h"
 
+#include <string>
+
 namespace water {
 
 //==============================================================================