linux-manual: clean up and improve (#380978)

{

  lib,

  stdenv,

  perl,

  linuxPackages_latest,

  perl,

  man,

}:

stdenv.mkDerivation rec {

stdenv.mkDerivation {

  pname = "linux-manual";

  inherit (linuxPackages_latest.kernel) version src;

  nativeBuildInputs = [ perl ];

  nativeInstallCheckInputs = [ man ];

  dontConfigure = true;

  dontBuild = true;

  doInstallCheck = true;

  postPatch = ''

    patchShebangs --build \

  '';

  installPhase = ''

    mandir=$out/share/man/man9

    mkdir -p $mandir

    runHook preInstall

    KBUILD_BUILD_TIMESTAMP=$(stat -c %Y Makefile) \

    export mandir="$out/share/man/man9"

    mkdir -p "$mandir"

    KBUILD_BUILD_TIMESTAMP="$(date -u -d "@$SOURCE_DATE_EPOCH")" \

    grep -F -l -Z \

      --exclude-dir Documentation \

      --exclude-dir tools \

      -R '/**' \

      | xargs -0 -n 256 -P $NIX_BUILD_CORES \

        $SHELL -c '{ scripts/kernel-doc -man "$@" || :; } \

          | scripts/split-man.pl '$mandir kernel-doc

      | xargs -0 -n 256 -P "$NIX_BUILD_CORES" \

        "$SHELL" -c '{ scripts/kernel-doc -man "$@" || :; } \

          | scripts/split-man.pl "$mandir"' kernel-doc

    runHook postInstall

  '';

  installCheckPhase = ''

    runHook preInstallCheck

    # Check for well‐known man page

    man -M "$out/share/man" -P cat 9 kmalloc >/dev/null

    test -f $mandir/kmalloc.9

    runHook postInstallCheck

  '';

  meta = with lib; {

  meta = {

    homepage = "https://kernel.org/";

    description = "Linux kernel API manual pages";

    license = licenses.gpl2Only;

    maintainers = with maintainers; [ mvs ];

    license = lib.licenses.gpl2Only;

    maintainers = with lib.maintainers; [ mvs ];

    platforms = lib.platforms.linux;

  };

}