ncurses 5.9 - patch 20120616

ncurses 5.9 - patch 20120616

+ add configure check to distinguish clang from gcc to eliminate
  warnings about unused command-line parameters when compiler warnings
  are enabled.
+ improve behavior when updating terminfo entries which are hardlinked
  by allowing for the possibility that an alias has been repurposed to
  a new primary name.
+ fix some strict compiler warnings based on package scripts.
+ further fixes for configure check for working poll (Debian #676461).