Add legal disclaimer to README.

README

@@ -108,7 +108,10 @@ Copyright notice:
 If you use the zlib library in a product, we would appreciate *not* receiving
 lengthy legal documents to sign.  The sources are provided for free but without
 warranty of any kind.  The library has been entirely written by Jean-loup
-Gailly and Mark Adler; it does not include third-party code.
+Gailly and Mark Adler; it does not include third-party code.  We make all
+contributions to and distributions of this project solely in our personal
+capacity, and are not conveying any rights to any intellectual property of
+any third parties.
 If you redistribute modified sources, we would appreciate that you include in
 the file ChangeLog history information documenting your changes.  Please read