Changes needed to install gevent with nix

python-packages.nix.diff

diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 910d763..3111e9a 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -5744,13 +5744,14 @@ let
     };
 
     buildInputs = with self; [ pkgs.libev ];
+    CFLAGS = stdenv.lib.optionalString stdenv.isDarwin "-std=gnu99";
     propagatedBuildInputs = optionals (!isPyPy) [ self.greenlet ];
 
     meta = {
       description = "Coroutine-based networking library";
       homepage = http://www.gevent.org/;
       license = licenses.mit;
-      platforms = platforms.linux;
+      platforms = platforms.unix;
       maintainers = with maintainers; [ bjornfor ];
     };
   };