ncurses 5.6 - patch 20080705

+ use NCURSES_MOUSE_MASK() in definition of BUTTON_RELEASE(), etc., to
  make those work properly with the "--enable-ext-mouse" configuration
  (cf: 20050205).
+ improve documentation of build-cc options in INSTALL.
+ work-around a bug in gcc 4.2.4 on AIX, which does not pass the
  -static/-dynamic flags properly to linker, causing test/bs to
  not link.