diff --git a/pkgs/development/libraries/zlib-mac-fix/darwin.patch b/pkgs/development/libraries/zlib-mac-fix/darwin.patch
new file mode 100644
index 00000000000..7a0a6902de4
--- /dev/null
+++ b/pkgs/development/libraries/zlib-mac-fix/darwin.patch
@@ -0,0 +1,22 @@
+diff -rc zlib-1.2.1/configure zlib-patched/configure
+*** zlib-1.2.1/configure	2003-11-17 04:50:39.000000000 +0100
+--- zlib-patched/configure	2004-08-05 19:18:59.000000000 +0200
+***************
+*** 89,97 ****
+               SHAREDLIB=libz$shared_ext
+               SHAREDLIBV=libz.$VER$shared_ext
+               SHAREDLIBM=libz.$VER1$shared_ext
+!              LDSHARED=${LDSHARED-"$cc -dynamiclib -install_name /usr/lib/$SHAREDLIBV -compatibility_version $VER2 -current_version $VER"}
+!              libdir='/usr/lib'
+!              includedir='/usr/include';;
+    *)             LDSHARED=${LDSHARED-"$cc -shared"};;
+    esac
+  else
+--- 89,95 ----
+               SHAREDLIB=libz$shared_ext
+               SHAREDLIBV=libz.$VER$shared_ext
+               SHAREDLIBM=libz.$VER1$shared_ext
+!              LDSHARED=${LDSHARED-"$cc -dynamiclib -install_name \${libdir}/$SHAREDLIBV -compatibility_version $VER2 -current_version $VER"};;
+    *)             LDSHARED=${LDSHARED-"$cc -shared"};;
+    esac
+  else
diff --git a/pkgs/development/libraries/zlib-mac-fix/default.nix b/pkgs/development/libraries/zlib-mac-fix/default.nix
new file mode 100644
index 00000000000..d602e7a0d45
--- /dev/null
+++ b/pkgs/development/libraries/zlib-mac-fix/default.nix
@@ -0,0 +1,12 @@
+{stdenv, fetchurl, patch}:
+
+stdenv.mkDerivation {
+  name = "zlib-1.2.1";
+  src = fetchurl {
+    url = http://www.gzip.org/zlib/zlib-1.2.1.tar.gz;
+    md5 = "ef1cb003448b4a53517b8f25adb12452";
+  };
+  configureFlags = "--shared";
+  patches = [./darwin.patch];
+  buildInputs = [patch];
+}
diff --git a/pkgs/stdenv/darwin-branch/default.nix b/pkgs/stdenv/darwin-branch/default.nix
new file mode 100644
index 00000000000..83a51c77b21
--- /dev/null
+++ b/pkgs/stdenv/darwin-branch/default.nix
@@ -0,0 +1,19 @@
+{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
new file mode 100644
index 00000000000..8a3cf6a99ba
--- /dev/null
+++ b/pkgs/stdenv/darwin-branch/prehook.sh
@@ -0,0 +1,6 @@
+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 e98151122b2..07494258f06 100644
--- a/pkgs/stdenv/generic-branch/setup.sh
+++ b/pkgs/stdenv/generic-branch/setup.sh
@@ -450,8 +450,16 @@ buildW() {
         return
     fi
 
+    if test -n "$preBuild"; then
+        $preBuild
+    fi
+    
     echo "make flags: $makeFlags"
     make $makeFlags || fail
+
+    if test -n "$postBuild"; then
+        $postBuild
+    fi
 }
 
 
@@ -545,6 +553,10 @@ distW() {
         return
     fi
 
+    if test -n "$preDist"; then
+        $preDist
+    fi
+    
     if test -z "$distTarget"; then
         distTarget="dist"
     fi
@@ -563,6 +575,10 @@ distW() {
         # wildcards in there.
         cp -pvd $tarballs $out/tarballs
     fi
+
+    if test -n "$postDist"; then
+        $postDist
+    fi
 }
 
 
diff --git a/pkgs/system/all-packages-generic.nix b/pkgs/system/all-packages-generic.nix
index c5b2172ac68..1a72acb06d9 100644
--- a/pkgs/system/all-packages-generic.nix
+++ b/pkgs/system/all-packages-generic.nix
@@ -48,6 +48,8 @@ rec {
     inherit fetchurl stdenv;
   };
 
+  patch = if stdenv.system == "powerpc-darwin" then null else gnupatch;
+
   gnused = (import ../tools/text/gnused) {
     inherit fetchurl stdenv;
   };
@@ -204,8 +206,7 @@ rec {
   };
 
   gnumake = (import ../development/tools/build-managers/gnumake) {
-    inherit fetchurl stdenv;
-    patch = gnupatch;
+    inherit fetchurl stdenv patch;
   };
 
   bison = (import ../development/tools/parsing/bison) {
@@ -237,8 +238,7 @@ rec {
     nativeTools = false;
     nativeGlibc = false;
     gcc = (import ../development/compilers/gcc-3.4) {
-      inherit fetchurl stdenv noSysDirs;
-      patch = gnupatch;
+      inherit fetchurl stdenv patch noSysDirs;
       profiledCompiler = true;
     };
     binutils = stdenv.gcc.binutils;
@@ -250,8 +250,7 @@ rec {
     nativeTools = false;
     nativeGlibc = false;
     gcc = (import ../development/compilers/gcc-2.95) {
-      inherit fetchurl stdenv noSysDirs;
-      patch = gnupatch;
+      inherit fetchurl stdenv patch noSysDirs;
     };
     binutils = stdenv.gcc.binutils;
     glibc = stdenv.gcc.glibc;
@@ -331,15 +330,14 @@ rec {
   };
 
   realPerl = (import ../development/interpreters/perl) {
-    inherit fetchurl stdenv;
-    patch = gnupatch;
+    inherit fetchurl stdenv patch;
   };
 
   sysPerl = (import ../development/interpreters/sys-perl) {
     inherit stdenv;
   };
 
-  perl = if stdenv.system == "powerpc-darwin7.3.0" then sysPerl else realPerl;
+  perl = if stdenv.system == "powerpc-darwin" then sysPerl else realPerl;
 
   python = (import ../development/interpreters/python) {
     inherit fetchurl stdenv zlib;
@@ -359,8 +357,7 @@ rec {
   };
 
   glibc = (import ../development/libraries/glibc) {
-    inherit fetchurl stdenv kernelHeaders;
-    patch = gnupatch;
+    inherit fetchurl stdenv kernelHeaders patch;
   };
 
   aterm = (import ../development/libraries/aterm) {
@@ -411,9 +408,14 @@ rec {
     inherit fetchurl stdenv;
   };
 
-  zlib = (import ../development/libraries/zlib) {
-    inherit fetchurl stdenv;
-  };
+  zlib = if stdenv.system == "powerpc-darwin" then
+    (import ../development/libraries/zlib-mac-fix) {
+      inherit fetchurl stdenv patch;
+    }
+  else
+    (import ../development/libraries/zlib) {
+      inherit fetchurl stdenv;
+    };
 
   libjpeg = (import ../development/libraries/libjpeg) {
     inherit fetchurl stdenv;
@@ -509,8 +511,7 @@ rec {
   };
 
   xlibs = (import ../development/libraries/xlibs) {
-    inherit fetchurl stdenv pkgconfig freetype expat;
-    patch = gnupatch;
+    inherit fetchurl stdenv pkgconfig freetype expat patch;
   };
 
   mesa = (import ../development/libraries/mesa) {
@@ -564,13 +565,11 @@ rec {
   };
 
   utillinux = (import ../os-specific/linux/util-linux) {
-    inherit fetchurl stdenv;
-    patch = gnupatch;
+    inherit fetchurl stdenv patch;
   };
 
   sysvinit = (import ../os-specific/linux/sysvinit) {
-    inherit fetchurl stdenv;
-    patch = gnupatch;
+    inherit fetchurl stdenv patch;
   };
 
   e2fsprogs = (import ../os-specific/linux/e2fsprogs) {
@@ -710,9 +709,8 @@ rec {
   ### MISC
 
   uml = (import ../misc/uml) {
-    inherit fetchurl stdenv perl;
+    inherit fetchurl stdenv perl patch;
     m4 = gnum4;
-    patch = gnupatch;
   };
 
   umlutilities = (import ../misc/uml-utilities) {
diff --git a/pkgs/system/all-packages.nix b/pkgs/system/all-packages.nix
index 1de35dcaa4b..382e004212e 100644
--- a/pkgs/system/all-packages.nix
+++ b/pkgs/system/all-packages.nix
@@ -12,6 +12,6 @@
   # Select the right instantiation.
   body =
     if system == "i686-linux" then stdenvs.stdenvLinuxPkgs
-    else if system == "powerpc-darwin7.3.0" then stdenvs.stdenvDarwinPkgs
+    else if system == "powerpc-darwin" then stdenvs.stdenvDarwinPkgs
     else stdenvs.stdenvNativePkgs;
 }
diff --git a/pkgs/system/powerpc-darwin.nix b/pkgs/system/powerpc-darwin.nix
index e5cb8cb0744..48c9164b14b 100644
--- a/pkgs/system/powerpc-darwin.nix
+++ b/pkgs/system/powerpc-darwin.nix
@@ -1 +1 @@
-(import ./all-packages.nix) {system = "powerpc-darwin7.3.0";}
+(import ./all-packages.nix) {system = "powerpc-darwin";}
diff --git a/pkgs/system/stdenvs.nix b/pkgs/system/stdenvs.nix
index 23bfa3c20ae..1ccd5079d03 100644
--- a/pkgs/system/stdenvs.nix
+++ b/pkgs/system/stdenvs.nix
@@ -157,10 +157,11 @@
     genericStdenv = import ../stdenv/generic-branch;
     inherit gccWrapper;
   };
-  
-  stdenvLinuxTestPkgs = allPackages {
-    stdenv = stdenvLinuxTest;
-    bootCurl = stdenvLinuxBoot2Pkgs.curl;
+
+  stdenvDarwinTest = (import ../stdenv/darwin-branch) {
+    stdenv = stdenvInitial;
+    genericStdenv = import ../stdenv/generic-branch;
+    inherit gccWrapper;
   };
-  
+    
 }