Replace some _MSC_VER with _WIN32.
This allows to use some code for mingw which was previously only
used for MSVC.

llvm-svn: 203651
diff --git a/lldb/source/Host/common/File.cpp b/lldb/source/Host/common/File.cpp
index 1051757..500b03c 100644
--- a/lldb/source/Host/common/File.cpp
+++ b/lldb/source/Host/common/File.cpp
@@ -887,7 +887,7 @@
     {
         m_is_interactive = eLazyBoolNo;
         m_is_real_terminal = eLazyBoolNo;
-#ifdef _MSC_VER
+#ifdef _WIN32
         if (_isatty(fd))
         {
             m_is_interactive = eLazyBoolYes;