Major work on the mingw stdenv. Basics now works.

- clone of fetchurl that invokes a given chmod to workaround problems
with inappropriate file permissions (executable files are not allowed
by Nix)

- cygpath tool to determine the full windows path of a cygwin
tool. This tool is used to give fetchurl the windows path to chmod.

- native curl.exe

- gcc-wrapper no longer used

- all-packages.nix: allows stdenv to specify fetchurl.


svn path=/nixpkgs/trunk/; revision=6140

pkgs/top-level/all-packages.nix

@@ -78,9 +78,16 @@ rec {
 
   ### BUILD SUPPORT
 
-  fetchurl = (import ../build-support/fetchurl) {
-    inherit stdenv curl;
-  };
+  /**
+   * Allow the stdenv to determine fetchurl, to cater for strange requirements.
+   */
+  fetchurl =
+    if stdenv ? fetchurl then
+      stdenv.fetchurl
+    else
+      (import ../build-support/fetchurl) {
+        inherit stdenv curl;
+      };
 
   fetchsvn = (import ../build-support/fetchsvn) {
     inherit stdenv subversion nix openssh;