hplip: add -n to gzip to improve reproducibility

(cherry picked from commit 1422563f54681f3ea3805fa1b8f3571f20dd7e19)

pkgs/misc/drivers/hplip/default.nix

@@ -101,10 +101,11 @@ python3Packages.buildPythonApplication {
     ./hplip-3.20.11-nixos-cups-ppd-search-path.patch
   ];
 
-  prePatch = ''
+  postPatch = ''
     # https://github.com/NixOS/nixpkgs/issues/44230
     substituteInPlace createPPD.sh \
-    --replace ppdc "${cups}/bin/ppdc"
+      --replace ppdc "${cups}/bin/ppdc" \
+      --replace "gzip -c" "gzip -cn"
 
     # HPLIP hardcodes absolute paths everywhere. Nuke from orbit.
     find . -type f -exec sed -i \
@@ -153,6 +154,12 @@ python3Packages.buildPythonApplication {
     export CUPS_DATADIR="${cups}/share/cups"
   '';
 
+  postConfigure = ''
+    # don't save timestamp, in order to improve reproducibility
+    substituteInPlace Makefile \
+      --replace "GZIP_ENV = --best" "GZIP_ENV = --best -n"
+  '';
+
   enableParallelBuilding = true;
 
   #