openssl: Fix target settings when building for GNU/hurd

GNU/hurd cross-build succeeds now!

svn path=/nixpkgs/trunk/; revision=30452

pkgs/development/libraries/openssl/default.nix

@@ -7,7 +7,6 @@ let
     (throw "openssl needs its platform name cross building" null)
     stdenv.cross;
 
-  # openssl only defines _GNU_SOURCE on Linux by default, but we need it on GNU
   hurdGNUSourcePatch = fetchurl {
     url = http://patch-tracker.debian.org/patch/series/dl/openssl/1.0.0e-2.1/gnu_source.patch;
     sha256 = "0zp4x8bql92fbqywnigqfsfj2vvabb66wv6g6zgzh0y6js1ic4pn";
@@ -48,7 +47,16 @@ stdenv.mkDerivation {
       export configureFlags="--libdir=lib --cross-compile-prefix=${stdenv.cross.config}- shared ${opensslCrossSystem}"
     '';
 
-    patches = stdenv.lib.optional (opensslCrossSystem == "hurd-x86") hurdGNUSourcePatch;
+    patches = stdenv.lib.optionals (opensslCrossSystem == "hurd-x86") [
+      # OpenSSL only defines _GNU_SOURCE on Linux, but we need it on GNU
+      hurdGNUSourcePatch
+
+      # Use the target settings from Debian's "debian-hurd-i386" target.
+      # see http://patch-tracker.debian.org/patch/series/view/openssl/1.0.0e-2.1/debian-targets.patch
+      # In particular, this sets the shared library extension properly so that
+      # make install succeeds
+      ./hurd-target.patch
+    ];
 
     postInstall = ''
       # Openssl installs readonly files, which otherwise we can't strip.