add patch for boost to get rid of ' what(): locale::facet::_S_create_c_locale name not valid' errors in some packages

svn path=/nixpkgs/trunk/; revision=26500

pkgs/development/libraries/boost/default.nix

@@ -59,6 +59,16 @@ stdenv.mkDerivation {
 
   installPhase = ":";
 
+  patches = [
+    # Patch to get rid of following error, experienced by some packages like encfs, bitcoin:
+    #    terminate called after throwing an instance of 'std::runtime_error'
+    #    what():  locale::facet::_S_create_c_locale name not valid
+    (fetchurl { 
+       url = https://svn.boost.org/trac/boost/raw-attachment/ticket/4688/boost_filesystem.patch ;
+       sha256 = "15k91ihzs6190pnryh4cl0b3c2pjpl9d790mr14x16zq52y7px2d"; 
+     })
+  ];
+  
   crossAttrs = rec {
     buildInputs = [ expat.hostDrv zlib.hostDrv bzip2.hostDrv ];
     # all buildInputs set previously fell into propagatedBuildInputs, as usual, so we have to