Fix module warnings

Author: mborland

modules/decimal.cxx

@@ -123,7 +123,17 @@ struct numeric_limits<boost::decimal::decimal128_fast>;
 
 // MSVC wants <boost/decimal> to be imported but also does not support importing it...
 #ifdef _MSC_VER
+#  pragma warning( push )
 #  pragma warning( disable : 5244 )
+#elif defined(__clang__)
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Winclude-angled-in-module-purview"
 #endif
 
 #include <boost/decimal.hpp>
+
+#ifdef _MSC_VER
+#  pragma warning( pop )
+#elif defined(__clang__)
+#  pragma clang diagnostic pop
+#endif