MSC_VER <= 1200 isn't supported; remove dead code

VisualStudio 6 and earlier aren't supported.

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4263)
diff --git a/CHANGES b/CHANGES
index f9b58f9..2cf6993 100644
--- a/CHANGES
+++ b/CHANGES
@@ -9,6 +9,10 @@
 
  Changes between 1.1.0f and 1.1.1 [xx XXX xxxx]
 
+  *) Some macro definitions to support VS6 have been removed.  Visual
+     Studio 6 has not worked since 1.1.0
+     [Rich Salz]
+
   *) Add ERR_clear_last_mark(), to allow callers to clear the last mark
      without clearing the errors.
      [Richard Levitte]