Suppress and/or fix warnings - in particular avoid undefined behaviour in the test cases!

[SVN r57859]

include/boost/integer/integer_mask.hpp

@@ -70,6 +70,11 @@ struct low_bits_mask_t
       BOOST_STATIC_CONSTANT( std::size_t, bit_count = limits_type::digits );    \
   }
 
+#ifdef BOOST_MSVC
+#pragma warning(push)
+#pragma warning(disable:4245)  // 'initializing' : conversion from 'int' to 'const boost::low_bits_mask_t<8>::least', signed/unsigned mismatch
+#endif
+
 BOOST_LOW_BITS_MASK_SPECIALIZE( unsigned char );
 
 #if USHRT_MAX > UCHAR_MAX
@@ -84,6 +89,10 @@ BOOST_LOW_BITS_MASK_SPECIALIZE( unsigned int );
 BOOST_LOW_BITS_MASK_SPECIALIZE( unsigned long );
 #endif
 
+#ifdef BOOST_MSVC
+#pragma warning(pop)
+#endif
+
 #undef BOOST_LOW_BITS_MASK_SPECIALIZE
 
 

include/boost/integer_traits.hpp

@@ -27,6 +27,17 @@
 #include <wchar.h>
 #endif
 
+//
+// We simply cannot include this header on gcc without getting copious warnings of the kind:
+//
+// ../../../boost/integer_traits.hpp:164:66: warning: use of C99 long long integer constant
+//
+// And yet there is no other reasonable implementation, so we declare this a system header
+// to suppress these warnings.
+//
+#if defined(__GNUC__) && (__GNUC__ >= 4)
+#pragma GCC system_header
+#endif
 
 namespace boost {
 template<class T>