shogun: fix CMake targets

CMake uses the directory of the configuration files to calculate
the path to the installed library and headers. But now that shogun uses
multiple outputs, this results in the $dev output being used for the
location of the shared library instead of $out.

Path the targets file to use the right location for the shared library.

pkgs/applications/science/machine-learning/shogun/default.nix

@@ -177,6 +177,12 @@ stdenv.mkDerivation rec {
     rm -r $out/share
   '';
 
+  postFixup = ''
+    # CMake incorrectly calculates library path from dev prefix
+    substituteInPlace $dev/lib/cmake/shogun/ShogunTargets-release.cmake \
+      --replace "\''${_IMPORT_PREFIX}/lib/" "$out/lib/"
+  '';
+
   meta = with lib; {
     description = "A toolbox which offers a wide range of efficient and unified machine learning methods";
     homepage = "http://shogun-toolbox.org/";