This adds a new "arrow" key "delete" corresponding to the kD termcap value.
It only works if that is a sequence such as "\033[3~"; if it is "\177", the
em-delete-prev-char or ed-delete-prev-char from the single-character
mappings remains. It turns out that most terminals (xterm and alikes,
syscons in xterm mode) produce "\033[3~" by default so <Delete> has the
expected effect.
This also means that things need to be considerably misconfigured for
<Backspace> to perform a <Delete> action.
el.c 1.44, el.h 1.17, editline.3 1.53, histedit.h 1.31:
# add EL_GETFP, and EL_SETFP.
el.c 1.42, term.c 1.46, term.h 1.18, editline.3 1.52, histedit.h 1.29:
# - Add more readline functions, enough for gdb-6.5
# - Make el_get varyadic, and implement EL_GETTC.
# - XXX: the EL_SETTC api will change in the future.
Note: The latter change breaks the ABI of the el_get() function.
Approved by: re (kensmith)
