Fix overflow warning in print_helper.hpp. #398

- (Implicitly) printing a big enough type results in:
  "warning: overflow in expression; result is 2147483347 with type 'int' [-Winteger-overflow]".
- Fixed by promoting the calculation to 'std::streamsize'.

include/boost/test/tools/detail/print_helper.hpp

@@ -97,7 +97,7 @@ struct print_log_value {
  std::streamsize set_precision( std::ostream& ostr, mpl::false_ )
  {
  if( std::numeric_limits<T>::is_specialized && std::numeric_limits<T>::radix == 2 )
- return ostr.precision( 2 + std::numeric_limits<T>::digits * 301/1000 );
+ return ostr.precision( 2 + std::streamsize(std::numeric_limits<T>::digits) * 301/1000 );
  else if ( std::numeric_limits<T>::is_specialized && std::numeric_limits<T>::radix == 10 ) {
 #ifdef BOOST_NO_CXX11_NUMERIC_LIMITS
  // (was BOOST_NO_NUMERIC_LIMITS_LOWEST but now deprecated).