libvirt: Fix incorrect path to pkttyagent

pkgs/development/libraries/libvirt/default.nix

@@ -26,6 +26,7 @@
 , ninja
 , perl
 , perlPackages
+, polkit
 , pkg-config
 , pmutils
 , python3
@@ -227,6 +228,9 @@ stdenv.mkDerivation rec {
         --replace "gmake" "make" \
         --replace "ggrep" "grep"
 
+      substituteInPlace src/util/virpolkit.h \
+        --replace '"/usr/bin/pkttyagent"' '"${polkit.bin}/bin/pkttyagent"'
+
       patchShebangs .
     ''
     + (lib.concatStringsSep "\n" (lib.mapAttrsToList patchBuilder overrides));