NaCl docs: update version information

native_client_sdk/src/doc/reference/pnacl-c-cpp-language-support.rst

 ============================
 PNaCl C/C++ Language Support
 ============================
 
 .. contents::
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 Source language support
 =======================
 
 The currently supported languages are C and C++. The PNaCl toolchain is
-based on Clang 3.3, which fully supports C++11 and most of C11. A
+based on recent Clang, which fully supports C++11 and most of C11. A
 detailed status of the language support is available `here
 <http://clang.llvm.org/cxx_status.html>`_.
 
 For information on using languages other than C/C++, see the :ref:`FAQ
 section on other languages <other_languages>`.
 
 As for the standard libraries, the PNaCl toolchain is currently based on
-``libc++``, and the ``newlib`` standard C library (version is available
-through the macro ``NEWLIB_VERSION``). ``libstdc++`` is also supported
-but its use is discouraged; see :ref:`building_cpp_libraries` for more
-details.
+``libc++``, and the ``newlib`` standard C library. ``libstdc++`` is also
+supported but its use is discouraged; see :ref:`building_cpp_libraries`
+for more details.
+
+Versions
+--------
+
+Version information can be obtained:
+
+* Clang/LLVM: run ``pnacl-clang -v``.
+* ``newlib``: use the ``_NEWLIB_VERSION`` macro.
+* ``libc++``: use the ``_LIBCPP_VERSION`` macro.
+* ``libstdc++``: use the ``_GLIBCXX_VERSION`` macro.
 
 Preprocessor definitions
 ------------------------
 
 When compiling C/C++ code, the PNaCl toolchain defines the ``__pnacl__``
 macro. In addition, ``__native_client__`` is defined for compatibility
 with other NaCl toolchains.
 
 .. _memory_model_and_atomics:
 
@@ skipping 243 matching lines @@
   A similar feature is **thread suspension**: The ability to
   asynchronously suspend and resume a thread and inspect or modify its
   execution state (such as register state).
 
   Neither PNaCl nor NaCl currently support asynchronous interruption
   or suspension of threads.
 
 If PNaCl were to support either of these, the interaction of
 ``volatile`` and atomics with same-thread signal handling would need
 to be carefully detailed.