* curl: build with OpenSSL (https) support by default.

* Some fetchurl-related refactoring.  The `realCurl' attribute is
  gone, `curl' is the real thing.  To prevent an infinite recursion in
  `fetchurl' (because it depends on curl and building curl needs
  fetchurl), curl and its dependencies (openssl, zlib, perl) use
  `fetchurlBoot', which is the fetchurl used by the previous bootstrap
  phase (e.g. the statically linked version of curl for
  stdenv-linux).  So as a result you can use https:// urls almost
  everywhere.

  There's also some hackery to prevent a different curl from being
  built in every stdenv-linux bootstrap phase (namely the
  stdenv.fetchurl attribute which allows fetchurl to be overriden
  everywhere).

svn path=/nixpkgs/trunk/; revision=11905

pkgs/tools/networking/curl/default.nix

@@ -18,7 +18,14 @@ stdenv.mkDerivation {
   CFLAGS = if stdenv ? isDietLibC then "-DHAVE_INET_NTOA_R_2_ARGS=1" else "";
   CXX = "g++";
   CXXCPP = "g++ -E";
-  inherit sslSupport openssl;
+
+  passthru = {
+    inherit sslSupport openssl;
+  };
+
+  preConfigure = ''
+    substituteInPlace configure --replace /usr/bin /no-such-path
+  '';
 
   patches = [
     /* Fixes broken retry support when a timeout is used.  The