Remove libmpcdec bundled lib, no longer used

Musepack support was removed in 857c50d.

SConstruct

@@ -145,7 +145,6 @@ opts.Add('vsproj', "Generate Visual Studio Project. (yes/no)", 'no')
 # Thirdparty libraries
 opts.Add('builtin_enet', "Use the builtin enet library (yes/no)", 'yes')
 opts.Add('builtin_freetype', "Use the builtin freetype library (yes/no)", 'yes')
-opts.Add('builtin_libmpcdec', "Use the builtin libmpcdec library (yes/no)", 'yes')
 opts.Add('builtin_libogg', "Use the builtin libogg library (yes/no)", 'yes')
 opts.Add('builtin_libpng', "Use the builtin libpng library (yes/no)", 'yes')
 opts.Add('builtin_libtheora', "Use the builtin libtheora library (yes/no)", 'yes')

thirdparty/README.md

@@ -53,19 +53,6 @@ Files extracted from upstream source:
 - `jpgd.{c,h}`
 
 
-## libmpcdec
-
-- Upstream: https://www.musepack.net
-- Version: SVN somewhere between SV7 and SV8 (r475)
-- License: BSD-3-Clause
-
-Files extracted from upstream source:
-
-- all .c and .h files in libmpcdec/
-- include/mpc as mpc/
-- COPYING from libmpcdec/
-
-
 ## libogg
 
 - Upstream: https://www.xiph.org/ogg