THRIFT-4081: appveyor retooling - added mingw64 build as a second job to the CI build process
This closes #1205
diff --git a/lib/cpp/test/ZlibTest.cpp b/lib/cpp/test/ZlibTest.cpp
index a4387a9..25db4b8 100644
--- a/lib/cpp/test/ZlibTest.cpp
+++ b/lib/cpp/test/ZlibTest.cpp
@@ -21,7 +21,7 @@
#define _GNU_SOURCE // needed for getopt_long
#endif
-#if (_MSC_VER <= 1700)
+#if defined(_MSC_VER) && (_MSC_VER <= 1700)
// polynomial and std::fill_t warning happens in MSVC 2010, 2013, maybe others
// https://svn.boost.org/trac/boost/ticket/11426
#pragma warning(disable:4996)