the first user/group. Caused huge fun in error messages from large script.
Old: pgrep -u root,NoSuchUser,daemon -> pgrep: unknown user `root'
Now: pgrep -u root,NoSuchUser,daemon -> pgrep: unknown user `NoSuchUser'
* invoking pkill without any arguments gave a core
* an initial numeric prefix of a signal name was ignored, e.g. -88sigint
* argc was not updated when the signal number was decoded.