nix-prefetch-script: explicit GNU util usage (#470357)

pkgs/tools/package-management/nix-prefetch-scripts/default.nix

@@ -13,6 +13,7 @@
   gawk,
   gitMinimal,
   git-lfs,
+  gnugrep,
   gnused,
   jq,
   mercurial,
@@ -35,15 +36,7 @@ let
       installPhase = ''
         install -vD ${src} $out/bin/$name;
         wrapProgram $out/bin/$name \
-          --prefix PATH : ${
-            lib.makeBinPath (
-              deps
-              ++ [
-                coreutils
-                gnused
-              ]
-            )
-          } \
+          --prefix PATH : ${lib.makeBinPath (deps ++ [ coreutils ])} \
           --set HOME /homeless-shelter
       '';
 
@@ -63,6 +56,7 @@ rec {
   # we expect people to have a Nix implementation available ambiently.
   nix-prefetch-bzr = mkPrefetchScript "bzr" ../../../build-support/fetchbzr/nix-prefetch-bzr [
     breezy
+    gnused
   ];
   nix-prefetch-cvs = mkPrefetchScript "cvs" ../../../build-support/fetchcvs/nix-prefetch-cvs [ cvs ];
   nix-prefetch-darcs = mkPrefetchScript "darcs" ../../../build-support/fetchdarcs/nix-prefetch-darcs [
@@ -76,11 +70,14 @@ rec {
     gawk
     gitMinimal
     git-lfs
+    gnused
   ];
   nix-prefetch-hg = mkPrefetchScript "hg" ../../../build-support/fetchhg/nix-prefetch-hg [
     mercurial
   ];
   nix-prefetch-svn = mkPrefetchScript "svn" ../../../build-support/fetchsvn/nix-prefetch-svn [
+    gnugrep
+    gnused
     subversion
   ];
   nix-prefetch-pijul = mkPrefetchScript "pijul" ../../../build-support/fetchpijul/nix-prefetch-pijul [