py3c: fix build with darwin (#121447)

pkgs/development/libraries/py3c/default.nix

@@ -11,6 +11,11 @@ stdenv.mkDerivation rec {
     sha256 = "04i2z7hrig78clc59q3i1z2hh24g7z1bfvxznlzxv00d4s57nhpi";
   };
 
+  postPatch = lib.optionalString stdenv.cc.isClang ''
+    substituteInPlace test/setup.py \
+      --replace "'-Werror', " ""
+  '';
+
   makeFlags = [
     "prefix=${placeholder "out"}"
   ];
@@ -26,6 +31,6 @@ stdenv.mkDerivation rec {
     homepage = "https://github.com/encukou/py3c";
     description = "Python 2/3 compatibility layer for C extensions";
     license = licenses.mit;
-    maintainers = with maintainers; [ ajs124 ];
+    maintainers = with maintainers; [ ajs124 dotlambda ];
   };
 }