Release notes: Mention clang-cl's /Zc:dllexportInlines- flag

llvm-svn: 346640
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index eccc78dd..09f6568 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -102,6 +102,11 @@
   filename, a `#pragma hdrstop` inside the source marks the end of the
   precompiled code.
 
+- clang-cl has a new command-line option, ``/Zc:dllexportInlines-``, similar to
+  ``-fvisibility-inlines-hidden`` on non-Windows, that makes class-level
+  `dllexport` and `dllimport` attributes not apply to inline member functions.
+  This can significantly reduce compile and link times. See the `User's Manual
+  <UsersManual.html#the-zc-dllexportinlines-option>`_ for more info.
 - ...