ncurses 6.0 - patch 20160910

ncurses 6.0 - patch 20160910

+ trim dead code ifdef'd with HIDE_EINTR since 970830 (discussion with
  Leon Winter).
+ trim some obsolete/incorrect wording about EINTR from wgetch manual
  page (patch by Leon Winter).
+ really correct 20100515 change (patch by Rich Coe).
+ add "--enable-string-hacks" option to test/configure
+ completed string-hacks for "sprintf", etc., including test-programs.
+ make "--enable-string-hacks" work with Debian by checking for the
  "bsd" library and its associated "<bsd/string.h>" header.