auto-patchelf: Don't use buildPythonApplication

https://github.com/NixOS/nixpkgs/pull/340162 introduced `autoPatchelfHook` as it's own top-level attribute.
This also made it use the Nixpkgs Python build infrastructure, which relies on dependency propagation, leaking Python as a dependency into many builds erroneously.

This change uses a `withPackages` constructed environment instead, and manually patches the script shebangs, not triggering the `buildPython*` dependency propagation mechanism

pkgs/by-name/au/auto-patchelf/package.nix

@@ -1,18 +1,29 @@
 {
+  stdenv,
+  python3,
   lib,
-  python3Packages,
 }:
 
-python3Packages.buildPythonApplication {
+let
+  pythonEnv = python3.withPackages (ps: [ ps.pyelftools ]);
+
+in
+# Note: Not using python3Packages.buildPythonApplication because of dependency propagation.
+stdenv.mkDerivation {
   pname = "auto-patchelf";
   version = "0-unstable-2024-08-14";
-  pyproject = false;
+
+  buildInputs = [ pythonEnv ];
 
   src = ./source;
 
-  dependencies = with python3Packages; [
-    pyelftools
-  ];
+  buildPhase = ''
+    runHook preBuild
+
+    substituteInPlace auto-patchelf.py --replace-fail "@defaultBintools@" "$NIX_BINTOOLS"
+
+    runHook postBuild
+  '';
 
   installPhase = ''
     runHook preInstall
@@ -22,10 +33,6 @@ python3Packages.buildPythonApplication {
     runHook postInstall
   '';
 
-  makeWrapperArgs = [
-    "--set DEFAULT_BINTOOLS $NIX_BINTOOLS"
-  ];
-
   meta = {
     description = "Automatically patch ELF binaries using patchelf";
     mainProgram = "auto-patchelf";

pkgs/by-name/au/auto-patchelf/source/auto-patchelf.py

@@ -21,6 +21,9 @@ from elftools.elf.elffile import ELFFile  # type: ignore
 from elftools.elf.enums import ENUM_E_TYPE, ENUM_EI_OSABI  # type: ignore
 
 
+DEFAULT_BINTOOLS = "@defaultBintools@"
+
+
 @contextmanager
 def open_elf(path: Path) -> Iterator[ELFFile]:
     with path.open('rb') as stream:
@@ -425,7 +428,7 @@ interpreter_arch: str   = None # type: ignore
 libc_lib: Path          = None # type: ignore
 
 if __name__ == "__main__":
-    nix_support = Path(os.environ.get('NIX_BINTOOLS', os.environ['DEFAULT_BINTOOLS'])) / 'nix-support'
+    nix_support = Path(os.environ.get('NIX_BINTOOLS', DEFAULT_BINTOOLS)) / 'nix-support'
     interpreter_path = Path((nix_support / 'dynamic-linker').read_text().strip())
     libc_lib = Path((nix_support / 'orig-libc').read_text().strip()) / 'lib'