python3Packages.pyplatec: add compile flag

pkgs/development/python-modules/pyplatec/default.nix

···
     sha256 = "0kqx33flcrrlipccmqs78d14pj5749bp85b6k5fgaq2c7yzz02jg";
   };
 
+  env.NIX_CFLAGS_COMPILE = "-std=c++11";
+
   meta = with lib; {
     description = "Library to simulate plate tectonics with Python bindings";
     homepage    = "https://github.com/Mindwerks/plate-tectonics";
     license     = licenses.lgpl3;
-    broken      = stdenv.isLinux;
   };
 
 }