message: drakefile: Don't install in "/usr" by default.
  Having "/usr" has a default prefix means your "stdlib.h"
  header would be install as "/usr/include/stdlib.h". Any file
  including stdlib would then trigger the install, which
  obviously will err because of permissions.
diff: @@ -70,7 +70,7 @@ def configure(cxx_toolkit = None,
  python3 = None,
  python_version = None,
  enable_cryptographic_rotation = False,
  - prefix = '/usr',
  + prefix = False,
  valgrind = None,
  valgrind_tests = False,
  build_openssl_eay = False,
  