Exclude clang-cl from msvc workaround

Author: pdimov

test/algorithm.cpp

@@ -23,13 +23,13 @@
     #define _SCL_SECURE_NO_WARNINGS
 #endif
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(__clang__)
     // counting_iterator generates a warning about truncating an integer
     #pragma warning(push)
     #pragma warning(disable : 4244)
 #endif
 #include <boost/iterator/counting_iterator.hpp>
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(__clang__)
     template ::boost::counting_iterator<int>;
     #pragma warning(pop)
 #endif