diff --git a/pkgs/overlays.nix b/pkgs/overlays.nix
--- a/pkgs/overlays.nix
+++ b/pkgs/overlays.nix
@@ -45,13 +45,14 @@ self: super: {
   # Override subversion derivation to
   #  - activate special python bindings
   subversionrc =
+
   let
     py3c = self.python38Packages.buildPythonPackage rec {
         pname = "py3c";
-        version = "1.0";
+        version = "1.1";
         src = self.fetchurl {
-          url = "https://files.pythonhosted.org/packages/6a/aa/9f1a69a8c71e72553b281603633e42501de932aa4d9912bccbf9a2884093/py3c-1.0.tar.gz";
-          sha256 = "1h80jqi6r64kppxb4kshsiadrgc5hwk5arp3zcki01jf4ahknjz9";
+          url = "https://github.com/encukou/py3c/archive/v1.1.tar.gz";
+          sha256 = "086xxccgzr4zkhsjkbcakydghrmll3rkxdcxhp5d1pidr4mw5zy7";
         };
         format = "setuptools";
         doCheck = false;
@@ -62,14 +63,16 @@ self: super: {
         meta = {
           license = [  ];
         };
+
+        preBuild = ''
+            make install
+        '';
     };
-  in
-  let
+
     pythonWithEnv = self.python38Packages.python.buildEnv.override {
         extraLibs = [ py3c ];
     };
-  in
-  let
+
     subversionWithPython = super.subversion.override {
       httpSupport = true; # client must support http
       pythonBindings = true;
@@ -88,6 +91,7 @@ self: super: {
       configureFlags = oldAttrs.configureFlags ++ [
         " --with-lz4=internal"
         " --with-utf8proc=internal"
+        " --with-py3c=${py3c}/include/python3.8/py3c/"
       ];
   });
 
diff --git a/shell.nix b/shell.nix
--- a/shell.nix
+++ b/shell.nix
@@ -9,7 +9,7 @@
 let
 
   # Full runtime environment without the actual Python package
-  env = import ./default.nix {
+  PythonDepsEnv = import ./default.nix {
     inherit
       doCheck;
     pythonExternalOverrides = self: super: {
@@ -27,7 +27,7 @@ let
           attrs.nativeBuildInputs ++
           attrs.buildInputs ++
           attrs.propagatedBuildInputs ++ [
-          env
+          PythonDepsEnv
           pytest
           ipdb
           ipython