+20110423
+ + add check in test/configure for use_window, use_screen.
+ + add configure-checks for getopt's variables, which may be declared
+ as different types on some Unix systems.
+ + add check in test/configure for some legacy curses types of the
+ function pointer passed to tputs().
+ + modify init_pair() to accept -1's for color value after
+ assume_default_colors() has been called (Debian #337905).
+ + modify test/background.c, adding commmand-line options to demonstrate
+ assume_default_colors() and use_default_colors().
+