Created flatten_dependencies function that dummy packages can use to create sane install environments.

lib/spack/spack/directory_layout.py

@@ -33,6 +33,7 @@
 
 import llnl.util.tty as tty
 from llnl.util.filesystem import join_path, mkdirp
+from llnl.util.link_tree import *
 
 from spack.spec import Spec
 from spack.error import SpackError
@@ -131,6 +132,23 @@ def remove_extension(self, spec, ext_spec):
         raise NotImplementedError()
 
 
+    def flatten_dependencies(self, spec, flat_dir):
+        """Make each dependency of spec present in dir via symlink."""
+        for dep in spec.traverse(root=False):
+            name = dep.name
+
+            dep_path = self.path_for_spec(dep)
+            dep_files = LinkTree(dep_path)
+
+            os.mkdir(flat_dir+'/'+name)
+
+            conflict = dep_files.find_conflict(flat_dir+'/'+name)
+            if conflict:
+                raise DependencyConflictError(conflict)
+
+            dep_files.merge(flat_dir+'/'+name)
+
+
     def path_for_spec(self, spec):
         """Return an absolute path from the root to a directory for the spec."""
         _check_concrete(spec)