trivial-builders: add runCommandLocalOverridable, like runCommand, but supports standard hooks like postBuild, etc.

pkgs/additional/trivial-builders/default.nix

@@ -1,9 +1,22 @@
 { lib
-, runCommandLocal
 , rmDbusServicesInPlace
+, runCommandLocalOverridable
+, stdenv
 , symlinkJoin
 }:
 {
+  # like `runCommandLocal`, but can be `.overrideAttrs` and supports standard phases/hooks like `postBuild`, etc.
+  runCommandLocalOverridable = name: env: buildPhase: stdenv.mkDerivation {
+    inherit name;
+    preferLocalBuild = true;
+    dontUnpack = true;
+
+    buildPhase = lib.concatStringsSep "\n" [
+      "runHook preBuild"
+      buildPhase
+      "runHook postBuild"
+    ];
+  };
   # given some package and a path, extract the item at `${package}/${path}` into
   # its own package, but otherwise keeping the same path.
   # this is done by copying the bits, so as to avoid including the item's neighbors
@@ -12,7 +25,7 @@
     paths = if lib.isList path then path else [ path ];
     suffix = (lib.head paths) + (if paths != [ path ] then "-and-other-paths" else "");
   in
-    runCommandLocal "${pkg.pname or pkg.name}-${suffix}" { } ''
+    runCommandLocalOverridable "${pkg.pname or pkg.name}-${suffix}" { } ''
       for item in ${lib.escapeShellArgs paths}; do
         mkdir -p "$out/$(dirname $item)"
         cp -a "${pkg}/$item" "$out/$item"
@@ -24,7 +37,7 @@
     paths = if lib.isList path then path else [ path ];
     suffix = (lib.head paths) + (if paths != [ path ] then "-and-other-paths" else "");
   in
-    runCommandLocal "${pkg.pname or pkg.name}-${suffix}" { } ''
+    runCommandLocalOverridable "${pkg.pname or pkg.name}-${suffix}" { } ''
       for item in ${lib.escapeShellArgs paths}; do
         mkdir -p "$out/$(dirname $item)"
         ln -s "${pkg}/$item" "$out/$item"

pkgs/default.nix

@@ -87,6 +87,7 @@ let
       linkIntoOwnPackage
       rmDbusServices
       rmDbusServicesInPlace
+      runCommandLocalOverridable
     ;
     unftp = callPackage ./additional/unftp { };
     where-am-i = callPackage ./additional/where-am-i { };