diff --git a/pkgs/build-support/buildenv/builder.pl b/pkgs/build-support/buildenv/builder.pl
index cdd65cbc523a..71502c9f6683 100755
--- a/pkgs/build-support/buildenv/builder.pl
+++ b/pkgs/build-support/buildenv/builder.pl
@@ -10,7 +10,6 @@ STDOUT->autoflush(1);
 
 my $out = $ENV{"out"};
 
-
 my @pathsToLink = split ' ', $ENV{"pathsToLink"};
 
 sub isInPathsToLink {
@@ -153,7 +152,3 @@ my $manifest = $ENV{"manifest"};
 if ($manifest) {
     symlink($manifest, "$out/manifest") or die "cannot create manifest";
 }
-
-
-system("eval \"\$postBuild\"") == 0
-    or die "post-build hook failed";
diff --git a/pkgs/build-support/buildenv/default.nix b/pkgs/build-support/buildenv/default.nix
index abe2f37ec660..1bfada4fb627 100644
--- a/pkgs/build-support/buildenv/default.nix
+++ b/pkgs/build-support/buildenv/default.nix
@@ -2,7 +2,7 @@
 # a fork of the buildEnv in the Nix distribution.  Most changes should
 # eventually be merged back into the Nix distribution.
 
-{stdenv, perl}:
+{ perl, runCommand }:
 
 { name
 
@@ -25,8 +25,9 @@
   postBuild ? ""
 }:
 
-stdenv.mkDerivation {
-  inherit name manifest paths ignoreCollisions pathsToLink postBuild;
-  realBuilder = "${perl}/bin/perl";
-  args = ["-w" ./builder.pl];
-}
+runCommand name
+  { inherit manifest paths ignoreCollisions pathsToLink postBuild; }
+  ''
+    ${perl}/bin/perl -w ${./builder.pl}
+    eval "$postBuild"
+  ''
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 1021d65ddaa7..df199ae36ea4 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -233,9 +233,8 @@ let
     theAttrSet = arg;
   };
 
-  buildEnvScript = ../build-support/buildenv/builder.pl;
   buildEnv = import ../build-support/buildenv {
-    inherit stdenv perl;
+    inherit runCommand perl;
   };
 
   dotnetenv = import ../build-support/dotnetenv {