update of the copyright info of libcxx

debian/copyright

@@ -361,6 +361,7 @@ Files: utils/unittest/googletest/*
 Copyright: 2006-2008, Google Inc.
 License: BSD-3-Clause
 
+Files: libcxx/*
 License: BSD-3-Clause
  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
@@ -378,6 +379,58 @@ License: BSD-3-Clause
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
 
+Files: libcxx*/*
+Copyright: 2009-2012 by the contributors listed below
+ N: Howard Hinnant
+ E: hhinnant@apple.com
+ D: Architect and primary author of libc++
+ .
+ N: Marshall Clow
+ E: marshall@idio.com
+ E: mclow@qualcomm.com
+ D: Minor patches and bug fixes.
+ .
+ N: Bjorn Reese
+ E: breese@users.sourceforge.net
+ D: Initial regex prototype
+ .
+ N: David Chisnall
+ E: theraven at theravensnest dot org
+ D: FreeBSD and Solaris ports, libcxxrt support, some atomics work.
+ .
+ N: Ruben Van Boxem
+ E: vanboxem dot ruben at gmail dot com
+ D: Initial Windows patches.
+ .
+ N: Arvid Picciani
+ E: aep at exys dot org
+ D: Minor patches and musl port.
+ .
+ N: Craig Silverstein
+ E: csilvers@google.com
+ D: Implemented Cityhash as the string hash function on 64-bit machines
+ .
+ N: Google Inc.
+ D: Copyright owner and contributor of the CityHash algorithm
+ .
+ N: Jeffrey Yasskin
+ E: jyasskin@gmail.com
+ E: jyasskin@google.com
+ D: Linux fixes.
+ .
+ N: Jonathan Sauer
+ D: Minor patches, mostly related to constexpr
+ .
+ N: Richard Smith
+ D: Minor patches.
+ .
+ The list is sorted by surname and formatted to allow easy grepping and
+ beautification by scripts.  The fields are: name (N), email (E), web-address
+ (W), PGP key ID and fingerprint (P), description (D), and snail-mail address
+ (S).
+ .
+License: NCSA or MIT
+
 License: U-OF-I-BSD-LIKE
  ==============================================================================
  LLVM Release License