Taking into account CPPFLAGS for hardening.
Also, this package more or less expects libsass locally (when downloading
from pypi, source of libsass is included. So fixing some path and linking.
--- a/setup.py
+++ b/setup.py
@@ -140,11 +140,12 @@
         link_flags = ['-fPIC', '-lc++']
     else:
         link_flags = ['-fPIC', '-lstdc++']
+    link_flags.append('-lsass')
 
 sass_extension = Extension(
     '_sass',
     sources,
-    include_dirs=[os.path.join('.', 'libsass', 'include')],
+    #include_dirs=[os.path.join('.', 'libsass', 'include')],
     depends=headers,
     extra_compile_args=flags + [version_define],
     extra_link_args=link_flags,