- Issue #15234: For BerkelyDB and Sqlite, only add the found library and
  include directories if they aren't already being searched. This avoids
  an explicit runtime library dependency.
Merge 3.4
- fix merge conflict
Fixes for KFreeBSD and the Hurd:

- Issue #21274: Define PATH_MAX for GNU/Hurd in Python/pythonrun.c.

- Issue #21276: posixmodule: Don't define USE_XATTRS on KFreeBSD and the Hurd.

- Issue #21275: Fix a socket test on KFreeBSD.
- Merge 3.4
- Issue #21285: Refactor and fix curses configure check to always search
  in a ncursesw directory.
- Merge 3.4
fix ref count annotations on sphinx >= 1.2.1 (closes #21286)
merge 3.4
correct len signature in docstring (closes #21294)
merge 3.4