Remove unnecessary includes from cast_test.cpp.

test/cast_test.cpp

@@ -14,14 +14,8 @@
 //    3 Aug 99  Initial Version
 
 #include <iostream>
-#include <climits>
-#include <cfloat>   // for DBL_MAX (Peter Schmid)
 #include <boost/polymorphic_cast.hpp>
 
-#  if SCHAR_MAX == LONG_MAX
-#      error "This test program doesn't work if SCHAR_MAX == LONG_MAX"
-#  endif
-
 using namespace boost;
 using std::cout;