Merged revisions 50454 via svnmerge from

https://svn.boost.org/svn/boost/trunk

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  r50454 | eric_niebler | 2009-01-03 17:39:13 -0800 (Sat, 03 Jan 2009) | 1 line
  
  proto::expr is a valid mpl sequence
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[SVN r50496]

libs/proto

@@ -1 +1 @@
-Subproject commit bea6f7f4a01fa4c5ec79ac979cd7c33149ff7fc6
+Subproject commit c9dd9f41e0dd79fb1ca8cd9cf33f166740c84122