knot-resolver*_6: simplify path overrides

pkgs/by-name/kn/knot-resolver-manager_6/package.nix

@@ -23,7 +23,6 @@ python3Packages.buildPythonPackage {
   # But the install-time etc differs from a sensible run-time etc.
   postPatch = ''
     substitute '${knot-resolver.unwrapped.config_py}'/knot_resolver/constants.py ./python/knot_resolver/constants.py \
-      --replace-fail '${knot-resolver.unwrapped.out}/etc' '/etc' \
       --replace-fail '${knot-resolver.unwrapped.out}/sbin' '${knot-resolver}/bin'
   ''
   # On non-Linux let's simplify construction of the knot-resolver command line,

pkgs/by-name/kn/knot-resolver_6/package.nix

@@ -56,20 +56,12 @@ let
         excludes = [ "NEWS" ];
         hash = "sha256-3w33v8UfhGdA50BlkfHpQLFxg+5ELk0lp7RzgvkSzK8=";
       })
+      # Install-time paths sometimes differ from run-time paths in nixpkgs.
+      ./paths.patch
     ];
 
-    # Path fixups for the NixOS service.
     # systemd Exec* options are difficult to override in NixOS *if present*, so we drop them.
     postPatch = ''
-      patch meson.build <<EOF
-      @@ -50,2 +50,3 @@
-      -systemd_work_dir = prefix / get_option('localstatedir') / 'lib' / 'knot-resolver'
-      -systemd_cache_dir = prefix / get_option('localstatedir') / 'cache' / 'knot-resolver'
-      +systemd_work_dir  = '/var/lib/knot-resolver'
-      +systemd_cache_dir = '/var/cache/knot-resolver'
-      +run_dir = '/run/knot-resolver'
-      EOF
-
       sed -e '/^ExecStart=/d' -e '/^ExecReload=/d' \
         -i systemd/knot-resolver.service.in
     ''

pkgs/by-name/kn/knot-resolver_6/paths.patch

@@ -0,0 +1,14 @@
+--- a/meson.build
++++ b/meson.build
+@@ -50,2 +50,3 @@
+-systemd_work_dir = prefix / get_option('localstatedir') / 'lib' / 'knot-resolver'
+-systemd_cache_dir = prefix / get_option('localstatedir') / 'cache' / 'knot-resolver'
++systemd_work_dir  = '/var/lib/knot-resolver'
++systemd_cache_dir = '/var/cache/knot-resolver'
++run_dir = '/run/knot-resolver'
+
+--- a/python/knot_resolver/constants.py.in
++++ b/python/knot_resolver/constants.py.in
+@@ -12 +12 @@
+-ETC_DIR = Path("@etc_dir@")
++ETC_DIR = Path("/etc/knot-resolver")