ChangeLog renamed to NEWS

Follows the libabc "guidelines":
https://git.kernel.org/?p=linux/kernel/git/kay/libabc.git;a=blob;f=README;h=b4bed;hb=HEAD#l193
configure.ac: use -Wall -Wextra
src/afuse.c: fix user_options, silence all warnings

user_options was missing a field in its static initialization.