Developer policy amendment regarding confidentiality notices

Thanks to Daniel Berlin and Nadav Rotem for feedback and rewording!

Discussion:
  http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20131014/191677.html

Reviewed by: nrotem, dberlin

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192958 91177308-0d34-0410-b5e6-96231b3b80d8

docs/DeveloperPolicy.rst

@@ -68,6 +68,9 @@ of bugs and enhancements occurring in LLVM.  We really appreciate people who are
 proactive at catching incoming bugs in their components and dealing with them
 promptly.
 
+Please be aware that all public LLVM mailing lists are public and archived, and
+that notices of confidentiality or non-disclosure cannot be respected.
+
 .. _patch:
 .. _one-off patches:
 
@@ -107,6 +110,10 @@ rather than ``Content-Disposition: attachment``. Apple Mail gamely displays such
 a file inline, making it difficult to work with for reviewers using that
 program.
 
+When submitting patches, please do not add confidentiality or non-disclosure
+notices to the patches themselves.  These notices conflict with the `LLVM
+License`_ and may result in your contribution being excluded.
+
 .. _code review:
 
 Code Reviews