ncurses 5.7 - patch 20100522

ncurses 5.7 - patch 20100522

+ correct cross-compiling configure check for CF_MKSTEMP macro, by
  adding a check cache variable set by AC_CHECK_FUNC (report by
  Pierre Labastie).
+ simplify include-dependencies of make_hash and make_keys, to reduce
  the need for setting BUILD_CPPFLAGS in cross-compiling when the
  build- and target-machines differ.
+ repair broken-linker configuration by restoring a definition of SP
  variable to curses.priv.h, and adjusting for cases where sp-funcs
  are used.
+ improve configure macro CF_AR_FLAGS, allowing ARFLAGS environment
  variable to override (prompted by report by Pablo Cazallas).