diff --git a/pkgs/stdenv/darwin-branch/default.nix b/pkgs/stdenv/darwin-branch/default.nix
deleted file mode 100644
index 83a51c77b21..00000000000
--- a/pkgs/stdenv/darwin-branch/default.nix
+++ /dev/null
@@ -1,19 +0,0 @@
-{stdenv, genericStdenv, gccWrapper}:
-
-genericStdenv {
-  name = "stdenv-darwin";
-  preHook = ./prehook.sh;
-  initialPath = "/usr/local /usr /";
-
-  inherit stdenv;
-
-  gcc = gccWrapper {
-    name = "gcc-darwin";
-    nativeTools = true;
-    nativeGlibc = true;
-    nativePrefix = "/usr";
-    inherit stdenv;
-  };
-
-  shell = "/bin/bash";
-}
diff --git a/pkgs/stdenv/darwin-branch/prehook.sh b/pkgs/stdenv/darwin-branch/prehook.sh
deleted file mode 100644
index 8a3cf6a99ba..00000000000
--- a/pkgs/stdenv/darwin-branch/prehook.sh
+++ /dev/null
@@ -1,6 +0,0 @@
-export NIX_ENFORCE_PURITY=
-export NIX_DONT_SET_RPATH=1
-export NIX_NO_SELF_RPATH=1
-dontFixLibtool=1
-NIX_STRIP_DEBUG=0
-echo XXX $NIX_DONT_SET_RPATH
\ No newline at end of file
diff --git a/pkgs/stdenv/generic-branch/setup.sh b/pkgs/stdenv/generic-branch/setup.sh
index 07494258f06..8aa065d5943 100644
--- a/pkgs/stdenv/generic-branch/setup.sh
+++ b/pkgs/stdenv/generic-branch/setup.sh
@@ -203,19 +203,24 @@ ensureDir() {
 }
 
 
-# Redirect stdout/stderr to a `tee' process that writes the specified
-# file (and also to our original stdout).  This requires bash.  The
-# original stdout is saved in descriptor 3.
+# Redirect stdout/stderr to a named pipe connected to a `tee' process
+# that writes the specified file (and also to our original stdout).
+# The original stdout is saved in descriptor 3.
 startLog() {
     local logFile=${logNr}_$1
     logNr=$((logNr + 1))
     if test "$logPhases" = 1; then
         ensureDir $logDir
+
         exec 3>&1
+
         if test "$dontLogThroughTee" != 1; then
-            # Put this in an `eval' so that non-bash shells (or bash
-            # invoked as `sh') won't choke on parsing this file.
-            eval "exec > >(tee $logDir/$logFile) 2>&1"
+            # This required named pipes (fifos).
+            logFifo=$NIX_BUILD_TOP/log_fifo
+            test -p $logFifo || mkfifo $logFifo
+            tee $logDir/$logFile < $logFifo &
+            logTeePid=$!
+            exec > $logFifo 2>&1
         else
             exec > $logDir/$logFile 2>&1
         fi
@@ -232,6 +237,14 @@ logNr=0
 stopLog() {
     if test "$logPhases" = 1; then
         exec >&3 2>&1
+
+        # Wait until the tee process has died.  Otherwise output from
+        # different phases may be mixed up.
+        if test -n "$logTeePid"; then
+            wait $logTeePid
+            logTeePid=
+            rm $logFifo
+        fi
     fi
 }
 
diff --git a/pkgs/stdenv/nix-linux-branch/default.nix b/pkgs/stdenv/nix-linux-branch/default.nix
deleted file mode 100644
index 6b25ea7dc28..00000000000
--- a/pkgs/stdenv/nix-linux-branch/default.nix
+++ /dev/null
@@ -1,20 +0,0 @@
-{stdenv, glibc, pkgs, genericStdenv, gccWrapper}:
-
-genericStdenv {
-  name = "stdenv-nix-linux";
-  preHook = ./prehook.sh;
-  initialPath = (import ../nix/path.nix) {pkgs = pkgs;};
-
-  inherit stdenv;
-
-  gcc = gccWrapper {
-    name = pkgs.gcc.name;
-    nativeTools = false;
-    nativeGlibc = false;
-    inherit (pkgs) gcc binutils;
-    inherit stdenv glibc;
-    shell = pkgs.bash ~ /bin/sh;
-  };
-
-  shell = pkgs.bash ~ /bin/bash;
-}
diff --git a/pkgs/stdenv/nix-linux-branch/prehook.sh b/pkgs/stdenv/nix-linux-branch/prehook.sh
deleted file mode 100644
index 08bb6c0332c..00000000000
--- a/pkgs/stdenv/nix-linux-branch/prehook.sh
+++ /dev/null
@@ -1 +0,0 @@
-export NIX_ENFORCE_PURITY=1
diff --git a/pkgs/system/stdenvs.nix b/pkgs/system/stdenvs.nix
index 1ccd5079d03..3f1f3cbae93 100644
--- a/pkgs/system/stdenvs.nix
+++ b/pkgs/system/stdenvs.nix
@@ -150,7 +150,7 @@
 
 
   # Testing the new stdenv-linux (TODO: remove this eventually).
-  stdenvLinuxTest = (import ../stdenv/nix-linux-branch) {
+  stdenvLinuxTest = (import ../stdenv/nix-linux) {
     stdenv = stdenvLinuxBoot2;
     pkgs = stdenvLinuxBoot2Pkgs;
     glibc = stdenvLinuxGlibc;
@@ -158,7 +158,7 @@
     inherit gccWrapper;
   };
 
-  stdenvDarwinTest = (import ../stdenv/darwin-branch) {
+  stdenvDarwinTest = (import ../stdenv/darwin) {
     stdenv = stdenvInitial;
     genericStdenv = import ../stdenv/generic-branch;
     inherit gccWrapper;