Adding a cross compiler condition for sparc64 due to a gcc bug

svn path=/nixpkgs/trunk/; revision=20277

pkgs/top-level/all-packages.nix

@@ -1966,7 +1966,8 @@ let
     profiledCompiler = false;
     enableMultilib = false;
     # cross-building for ultrasparc in 4.4.3 will require disabling shared due to a gcc bug.
-    # enableShared = false;
+    # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41818
+    enableShared = if (cross.platform.arch == "sparc64") then true false else;
     crossStageStatic = false;
   };