khash: silence -Wunused-function for delta-islands
showing the following when compiled with latest clang (OpenBSD, Fedors
and macOS):
delta-islands.c:23:1: warning: unused function 'kh_destroy_str'
[-Wunused-function]
delta-islands.c:23:1: warning: unused function 'kh_clear_str'
[-Wunused-function]
delta-islands.c:23:1: warning: unused function 'kh_del_str' [-Wunused-function]
Reported-by: René Scharfe <l.s.r@web.de>
Suggested-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>