Can build with (original llvm) clang-cl on windows

src/libnest2d/tests/test.cpp

@@ -7,6 +7,10 @@
 #include "../tools/svgtools.hpp"
 #include <libnest2d/utils/rotcalipers.hpp>
 
+#if defined(_MSC_VER) && defined(__clang__)
+#define BOOST_NO_CXX17_HDR_STRING_VIEW
+#endif
+
 #include "boost/multiprecision/integer.hpp"
 #include "boost/rational.hpp"