Dimitry Andric:  many visibility fixes.  Howard:  Much appreciated.  Can you send me a patch to CREDITS.TXT?

llvm-svn: 163862
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: aeb85680fb688e96ba2d2fc7703ae6e57cc44097
diff --git a/include/ostream b/include/ostream
index e6dd4b5..b135ddb 100644
--- a/include/ostream
+++ b/include/ostream
@@ -169,7 +169,7 @@
 public:
 
     // 27.7.2.4 Prefix/suffix:
-    class sentry;
+    class _LIBCPP_VISIBLE sentry;
 
     // 27.7.2.6 Formatted output:
     basic_ostream& operator<<(basic_ostream& (*__pf)(basic_ostream&));