Give isCompatibleWithMSVC a better interface

We now use an enum which maps the marketing name (almost always a year)
to the major version number.

llvm-svn: 236967
diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index 17e41f6..aaf17a9 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -810,7 +810,7 @@
         OS << ',';
         // Visual Studio 2010 or earlier expects column number to be off by one
         if (LangOpts.MSCompatibilityVersion &&
-            LangOpts.MSCompatibilityVersion < 170000000)
+            !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2012))
           ColNo--;
       } else
         OS << ':';