MFC r219342, r219346:

MFC r219342, r219346:

r219342 (pjd):

Fix various issues in how %#T is handled:
- If precision is 0, don't print period followed by no digits.
- If precision is 0 stop printing units as soon as possible
  (eg. if we have three years and five days and precision is 0
   print only 3y5d).
- If precision is not 0, print all units (eg. 3y0d0h0m0s.00).

r219346 (pjd):

Because we call __printf_out() with a on-stack buffer, also call
__printf_flush() so we are sure it won't be referenced after we return.

Approved by:	kib (co-mentor), pjd (mentor)

git-svn-id: svn://svn.freebsd.org/base/stable/8@220138 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f