check_user_name) renamed to is_valid_user_name (resp.
is_valid_group_name). is_valid_user_name and is_valid_group_name
return a bool.
* src/grpck.c, src/newusers.c, src/usermod.c, src/useradd.c,
src/groupmod.c, src/pwck.c, src/groupadd.c: Use is_valid_user_name
and is_valid_group_name, following above change.
* libmisc/chkname.c: Avoid implicit conversion of chars to
booleans. Add brackets and parenthesis.
Files with no license use the default 3-clauses BSD license. The copyright
were mostly not recorded; they were updated according to the Changelog.
"Julianne Frances Haugh and contributors" changed to "copyright holders
and contributors".
