include,gallium: Remove pre-MSVC 2013 compatibility.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
diff --git a/include/c99_compat.h b/include/c99_compat.h
index 4be5b7e..b55ad9c 100644
--- a/include/c99_compat.h
+++ b/include/c99_compat.h
@@ -36,17 +36,17 @@
  */
 #if defined(_MSC_VER)
 
-#  if _MSC_VER < 1500
-#    error "Microsoft Visual Studio 2008 or higher required"
+#  if _MSC_VER < 1800
+#    error "Microsoft Visual Studio 2013 or higher required"
 #  endif
 
    /*
-    * Visual Studio 2012 will complain if we define the `inline` keyword, but
+    * Visual Studio will complain if we define the `inline` keyword, but
     * actually it only supports the keyword on C++.
     *
     * To avoid this the _ALLOW_KEYWORD_MACROS must be set.
     */
-#  if (_MSC_VER >= 1700) && !defined(_ALLOW_KEYWORD_MACROS)
+#  if !defined(_ALLOW_KEYWORD_MACROS)
 #    define _ALLOW_KEYWORD_MACROS
 #  endif