* lib/commonio.h: Include defines.h to get the definition of bool.
* lib/commonio.h: commonio_present returns a bool
* lib/commonio.c: Implement above changes.
* lib/commonio.c: add argument names in prototypes.
* lib/commonio.c: name_is_nis returns a bool.
* lib/commonio.c: nscd_need_reload is a bool.
* lib/commonio.c: Improve types (use size_t / pid_t when needed instead of int).
* lib/commonio.c: Avoid assignments in comparisons.
* lib/commonio.c: Add brackets and parenthesis.
* lib/commonio.c: Avoid implicit conversion of pointers / integers to booleans
* lib/commonio.c: The return values of utime is not checked on purpose.