Include <stdlib.h>.
(get_surrounding_text, delete_surrounding_text)
(get_preceding_char, get_following_char): New functions.
(integer_value): New arg surrounding. If it is nonzero, try to
get a surrounding character. Callers changed.
(take_action_list): Check `value' before setting an element.
(destroy_ic): Unref ic_info->preceding_text and
ic_info->following_text.
(minput__init): Initialize Minput_get_surrounding_text and
Minput_delete_surrounding_text.
(Minput_get_surrounding_text, Minput_delete_surrounding_text): New
variables.