diff --git a/pkgs/stdenv/generic/setup-new.sh b/pkgs/stdenv/generic/setup-new.sh
index 2561399695c4..b646c3ed7f12 100644
--- a/pkgs/stdenv/generic/setup-new.sh
+++ b/pkgs/stdenv/generic/setup-new.sh
@@ -442,34 +442,31 @@ stripHash() {
 
 
 unpackFile() {
-    local file="$1"
+    curSrc="$1"
     local cmd
 
-    header "unpacking source archive $file" 3
+    header "unpacking source archive $curSrc" 3
 
-    case "$file" in
+    case "$curSrc" in
         *.tar)
-            tar xvf $file
+            tar xvf $curSrc
             ;;
         *.tar.gz | *.tgz | *.tar.Z)
-            gzip -d < $file | tar xvf -
+            gzip -d < $curSrc | tar xvf -
             ;;
         *.tar.bz2 | *.tbz2)
-            bzip2 -d < $file | tar xvf -
+            bzip2 -d < $curSrc | tar xvf -
             ;;
         *.zip)
-            unzip $file
+            unzip $curSrc
             ;;
         *)
-            if test -d "$file"; then
-                stripHash $file
-                cp -prvd $file $strippedName
+            if test -d "$curSrc"; then
+                stripHash $curSrc
+                cp -prvd $curSrc $strippedName
             else
-                if test -n "$findUnpacker"; then
-                    $findUnpacker $1;
-                fi
                 if test -z "$unpackCmd"; then
-                    echo "source archive $file has unknown type"
+                    echo "source archive $curSrc has unknown type"
                     exit 1
                 fi
                 eval "$unpackCmd"
diff --git a/pkgs/tools/system/cron/default.nix b/pkgs/tools/system/cron/default.nix
index 4d7dcb93db2b..2f7bffcbe31d 100644
--- a/pkgs/tools/system/cron/default.nix
+++ b/pkgs/tools/system/cron/default.nix
@@ -7,7 +7,7 @@ stdenv.mkDerivation {
     md5 = "5e1be9dbde66295821ac7899f2e1f561";
   };
 
-  unpackCmd = "(mkdir cron && cd cron && sh $src)";
+  unpackCmd = "(mkdir cron && cd cron && sh $curSrc)";
 
   preBuild = "
     substituteInPlace Makefile --replace ' -o root' ' ' --replace 111 755
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 2d3c80d2a576..ff35b9b80507 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -584,7 +584,8 @@ let
   };
 
   cron = import ../tools/system/cron {
-    inherit fetchurl stdenv;
+    inherit fetchurl;
+    stdenv = stdenvNew;
   };
 
   curl = import ../tools/networking/curl {