Add NaCl SDK release note about LLVM 3.6 and debug metadata changes.

native_client_sdk/src/doc/sdk/release-notes.rst

Index: native_client_sdk/src/doc/sdk/release-notes.rst
diff --git a/native_client_sdk/src/doc/sdk/release-notes.rst b/native_client_sdk/src/doc/sdk/release-notes.rst
index 8fbf326861ab8a0a3b7b91385b87eaf17acb384e..b5029fbfa61072a1a401f417b546c25fbdb5c4f7 100644
--- a/native_client_sdk/src/doc/sdk/release-notes.rst
+++ b/native_client_sdk/src/doc/sdk/release-notes.rst
@@ -19,6 +19,14 @@ PNaCl
   SDK can therefore generate them.
 * Fix a `code generation bug on ARM`_ when dealing with 16-bit load/store and
   ``bswap`` which led to a NaCl validation failure.
+* PNaCl is now based on LLVM 3.6. If you are using GDB to debug PNaCl
+  :ref:`BC files with debug metadata in the browser<debugging_pnacl_pexes>`,
+  remember that the SDK version must match the in-browser translator version.

[binji, 2015/04/01 16:59:00]

how can the developer know that the SDK version matches the translator version?

[jvoung (off chromium), 2015/04/01 17:22:56]

Reworded to say use SDK version X for chrome version X.

Technically they could run "pnacl-clang --version" to get a NaCl git hash, and
then go to chrome://nacl to also get a NaCl git hash, but the compatibility
could be a bit fuzzy (especially on canary/dev) where sometimes the SDK gets
ahead of the chrome translator (and that is okay).

+  Bitcode debug metadata changed from LLVM 3.5 to 3.6. Otherwise, it is still

[binji, 2015/04/01 16:59:00]

"Otherwise" sounds weird here. Otherwise what?

[jvoung (off chromium), 2015/04/01 17:22:56]

Reworded -- is this better?

+  possible to work around this version-match issue by translating pexes to
+  nexes using the :ref:`offline translator in the same SDK
+  <debugging_pexes_via_nexes>` instead of using the translator in
+  the browser.
 
 .. _`code generation bug on ARM`: https://code.google.com/p/chromium/issues/detail?id=460432