20090927
+ move leak-checking for comp_captab.c into _nc_leaks_tinfo() since
that module since 20090711 is in libtinfo.
+ add configure option --enable-term-driver, to allow compiling with
terminal-driver. That is used in mingw port, and (being somewhat
more complicated) is an experimental alternative to the conventional
termlib internals. Currently, it requires the sp-funcs feature to
be enabled.
+ completed integrating "sp-funcs" by Juergen Pfeifer in ncurses
library (some work remains for forms library).