[FIX] gcc: remove the explicit jit install; libpam for shadow and util-linux

Disabling libgccjit took four separate cuts, and this is the fourth.
Removing the second configure pass, the pkgname entry and the _pick
lines still left package_gcc() calling

  make -C gcc DESTDIR="$pkgdir" jit.install-common jit.install-info

which fails on a library that was never built:

  install: cannot install libgccjit.so.0.0.1

The lesson repeats: in an Arch PKGBUILD a component is referenced in
several independent places -- the pkgname array, a build block, _pick
lines in package(), and explicit make targets. Removing it means
finding all four, and grepping for the component name after each cut is
the only way to know.

shadow and util-linux both stop on a missing libpam. Same family as
every host makedepend before them: invisible until a build names it,
because --nodeps forbids pacman from checking.

--- FR ---

Desactiver libgccjit aura demande quatre coupes distinctes, et voici la
quatrieme. Retirer la seconde passe de configuration, l entree de
pkgname et les lignes _pick laissait encore package_gcc() appeler

  make -C gcc DESTDIR="$pkgdir" jit.install-common jit.install-info

qui echoue sur une bibliotheque jamais batie :

  install: cannot install libgccjit.so.0.0.1

La lecon se repete : dans un PKGBUILD d Arch, un composant est
reference en plusieurs endroits independants -- le tableau pkgname, un
bloc de compilation, des lignes _pick dans package(), et des cibles
make explicites. Le retirer suppose de trouver les quatre, et chercher
son nom apres chaque coupe est le seul moyen de le savoir.

shadow et util-linux s arretent tous deux sur un libpam absent. Meme
famille que tous les makedepends d hote precedents : invisibles jusqu a
ce qu une compilation les nomme, puisque --nodeps interdit a pacman de
verifier.

Assisted-by: Claude Opus 5

patches/pkgbuild/gcc.sh

@@ -153,6 +153,13 @@ s = "\n".join(l for l in s.split("\n")
                and "mkdir -p \"$srcdir\"/libgccjit-build" not in l)
 io.open("PKGBUILD", "w", encoding="utf-8").write(s)
 PY
+    # package_gcc() also installs the jit artefacts explicitly:
+    #   make -C gcc DESTDIR="$pkgdir" jit.install-common jit.install-info
+    # Removing the build block and the pkgname entry was not enough --
+    # this line runs in the MAIN package function and fails on a library
+    # that was never built:
+    #   install: cannot install libgccjit.so.0.0.1
+    sed -i '/jit\.install-common/d' PKGBUILD
     if grep -q 'libgccjit-build' PKGBUILD; then
         echo "gcc: libgccjit build block remains" >&2; exit 1
     fi