Compile Fix: setenv() is not defined for mingw either

intern/cycles/blender/blender_python.cpp

@@ -491,7 +491,7 @@ static PyObject *system_info_func(PyObject * /*self*/, PyObject * /*value*/)
 static PyObject *opencl_disable_func(PyObject * /*self*/, PyObject * /*value*/)
 {
 	VLOG(2) << "Disabling OpenCL platform.";
-#ifdef _MSC_VER
+#ifdef WIN32
 	putenv("CYCLES_OPENCL_TEST=NONE");
 #else
 	setenv("CYCLES_OPENCL_TEST", "NONE", 1);