master updated (a49ecdd0ff -> 7c4a780721)

[Po Lu]

oldosfan pushed a change to branch master.

      from  a49ecdd0ff Keep subcommands in pipelines from clobbering the 
head/tail processes
       new  d63d633a68 Handle invalid NEWS files during describe-function
       new  7c4a780721 Prevent errors when Lisp code asks for props of invalid 
windows


Summary of changes:
 lisp/help-fns.el | 32 +++++++++++++++++---------------
 src/xfns.c       | 10 ++++++++++
 2 files changed, 27 insertions(+), 15 deletions(-)