libmsn: remove, build fails and obsolete

libmsn provides access to the MSN network, which was officially
shut down in October 2014. No packages depends on libmsn.

pkgs/development/libraries/libmsn/default.nix

@@ -1,15 +0,0 @@
-{stdenv, fetchurl, cmake, openssl}:
-
-stdenv.mkDerivation rec {
-  name = "libmsn-4.2.1";
-  src = fetchurl {
-    url = "mirror://sourceforge/libmsn/${name}.tar.bz2";
-    sha256 = "338369c7455b123e84b9a7a858ac0ed2b1dc32e6529f460fdc01d28869a20fde";
-  };
-  patches = [ ./fix-ftbfs-gcc4.7.diff ];
-  buildInputs = [ cmake openssl ];
-
-  meta = {
-    platforms = stdenv.lib.platforms.unix;
-  };
-}

pkgs/development/libraries/libmsn/fix-ftbfs-gcc4.7.diff

@@ -1,16 +0,0 @@
-Fix g++ 4.7 build failure
-
-Kudos to Matthias Klose for the patch
-
-Index: libmsn-4.2/msn/util.cpp
-===================================================================
---- libmsn-4.2.orig/msn/util.cpp	2009-07-22 19:57:10.000000000 +0000
-+++ libmsn-4.2/msn/util.cpp	2012-04-16 20:52:18.068767213 +0000
-@@ -25,6 +25,7 @@
- #include <msn/util.h>
- #include <sstream>
- #include <errno.h>
-+#include <unistd.h>
- #include <cctype>
- #include <fstream>
- #include <openssl/rand.h>

pkgs/top-level/all-packages.nix

@@ -9041,8 +9041,6 @@ with pkgs;
 
   libmrss = callPackage ../development/libraries/libmrss { };
 
-  libmsn = callPackage ../development/libraries/libmsn { };
-
   libmspack = callPackage ../development/libraries/libmspack { };
 
   libmusicbrainz2 = callPackage ../development/libraries/libmusicbrainz/2.x.nix { };