the list, not adduser. This fixes a segmentation fault for every
call of groupmems -d.
* libmisc/list.c: Add assertions to help identifying these issues.
* libmisc/list.c: Avoid implicit conversion of pointers to
booleans.
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".
