update COPYRIGHT file with additional contributor information

COPYRIGHT

@@ -1,6 +1,7 @@
 musl as a whole is licensed under the following standard MIT license:
 
-Copyright © 2005-2014 Rich Felker
+----------------------------------------------------------------------
+Copyright © 2005-2014 Rich Felker, et al.
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
@@ -20,12 +21,40 @@ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+----------------------------------------------------------------------
 
+Authors/contributors include:
 
-Portions of this software are contributed or derived from software
-authored by third parties. Complete details on the copyright status of
-all code included in musl follows below:
+Anthony G. Basile
+Arvid Picciani
+Bobby Bingham
+Boris Brezillon
+Chris Spiegel
+Emil Renner Berthing
+Hiltjo Posthuma
+Isaac Dunham
+Jens Gustedt
+Jeremy Huntwork
+John Spencer
+Justin Cormack
+Luca Barbato
+Luka Perkov
+Michael Forney
+Nicholas J. Kain
+orc
+Pascal Cuoq
+Pierre Carrier
+Rich Felker
+Richard Pennington
+Solar Designer
+Strake
+Szabolcs Nagy
+Timo Teräs
+Valentin Ochs
+William Haddon
 
+Portions of this software are derived from third-party works licensed
+under terms compatible with the above MIT license:
 
 The TRE regular expression implementation (src/regex/reg* and
 src/regex/tre*) is Copyright © 2001-2008 Ville Laurikari and licensed
@@ -33,15 +62,18 @@ under a 2-clause BSD license (license text in the source files). The
 included version has been heavily modified by Rich Felker in 2012, in
 the interests of size, simplicity, and namespace cleanliness.
 
-Most of the math library code (src/math/* and src/complex/*) is
+Much of the math library code (src/math/* and src/complex/*) is
 Copyright © 1993,2004 Sun Microsystems or
 Copyright © 2003-2011 David Schultz or
 Copyright © 2003-2009 Steven G. Kargl or
 Copyright © 2003-2009 Bruce D. Evans or
 Copyright © 2008 Stephen L. Moshier
-and labelled as such. All have been licensed under extremely
-permissive terms. See the comments in the individual files for
-details.
+and labelled as such in comments in the individual source files. All
+have been licensed under extremely permissive terms.
+
+The ARM memcpy code (src/string/armel/memcpy.s) is Copyright © 2008
+The Android Open Source Project and is licensed under a two-clause BSD
+license. It was taken from Bionic libc, used on Android.
 
 The implementation of DES for crypt (src/misc/crypt_des.c) is
 Copyright © 1994 David Burren. It is licensed under a BSD license.
@@ -74,22 +106,22 @@ The powerpc port was also originally written by Richard Pennington,
 and later supplemented and integrated by John Spencer. It is licensed
 under the standard MIT terms.
 
-The ARM memcpy code is Copyright © 2008 The Android Open Source
-Project and is licensed under a two-clause BSD license. It was taken
-from Bionic libc, used on Android.
-
 All other files which have no copyright comments are original works
-Copyright © 2005-2014 Rich Felker, the main author of this library.
-The decision to exclude such comments is intentional, as it should be
-possible to carry around the complete source code on tiny storage
-media. All public header files (include/* and arch/*/bits/*) should be
+produced specifically for use as part of this library, written either
+by Rich Felker, the main author of the library, or by one or more
+contibutors listed above. Details on authorship of individual files
+can be found in the git version control history of the project. The
+omission of copyright and license comments in each file is in the
+interest of source tree size.
+
+All public header files (include/* and arch/*/bits/*) should be
 treated as Public Domain as they intentionally contain no content
 which can be covered by copyright. Some source modules may fall in
 this category as well. If you believe that a file is so trivial that
-it should be in the Public Domain, please contact me and, if I agree,
-I will explicitly release it from copyright.
+it should be in the Public Domain, please contact the authors and
+request an explicit statement releasing it from copyright.
 
-The following files are trivial, in my opinion not copyrightable in
+The following files are trivial, believed not to be copyrightable in
 the first place, and hereby explicitly released to the Public Domain:
 
 All public headers: include/*, arch/*/bits/*