py-sip installs properly into a prefix

var/spack/packages/py-sip/package.py

 from spack import *
+import os
 
 class PySip(Package):
     """SIP is a tool that makes it very easy to create Python bindings for C and C++ libraries."""
@@ -10,6 +11,10 @@ class PySip(Package):
     extends('python')
 
     def install(self, spec, prefix):
-        python('configure.py')
+        python('configure.py',
+               '--destdir=%s' % site_packages_dir,
+               '--bindir=%s' % spec.prefix.bin,
+               '--incdir=%s' % python_include_dir,
+               '--sipdir=%s' % os.path.join(spec.prefix.share, 'sip'))
         make()
         make('install')

var/spack/packages/python/package.py

@@ -42,6 +42,11 @@ def python_lib_dir(self):
         return os.path.join('lib', 'python%d.%d' % self.version[:2])
 
 
+    @property
+    def python_include_dir(self):
+        return os.path.join('include', 'python%d.%d' % self.version[:2])
+
+
     @property
     def site_packages_dir(self):
         return os.path.join(self.python_lib_dir, 'site-packages')
@@ -58,8 +63,9 @@ def setup_dependent_environment(self, module, spec, ext_spec):
         module.python = Executable(join_path(spec.prefix.bin, 'python'))
 
         # Add variables for lib/pythonX.Y and lib/pythonX.Y/site-packages dirs.
-        module.python_lib_dir = os.path.join(ext_spec.prefix, self.python_lib_dir)
-        module.site_packages_dir = os.path.join(ext_spec.prefix, self.site_packages_dir)
+        module.python_lib_dir     = os.path.join(ext_spec.prefix, self.python_lib_dir)
+        module.python_include_dir = os.path.join(ext_spec.prefix, self.python_include_dir)
+        module.site_packages_dir  = os.path.join(ext_spec.prefix, self.site_packages_dir)
 
         # Make the site packages directory if it does not exist already.
         mkdirp(module.site_packages_dir)