* libmisc/limits.c: Avoid implicit conversion of pointers /
integers to booleans.
* libmisc/limits.c: Ignore the return value of umask(). We will
never return to the original umask.
* libmisc/limits.c: Avoid multi-statements lines.
* libmisc/limits.c: Added default to a switch(). Report invalid
limit strings to syslog.
* libmisc/limits.c: Ignore the return value of fclose().
/etc/limits is open read-only.
* libmisc/limits.c: Ignore the return value of fputs() and
sleep().
* libmisc/limits.c: Check the return value of nice() and
set_filesize_limit(), and report errors to syslog.
* libmisc/ulimit.c, lib/prototypes.h: Return failures of
set_filesize_limit(). Change the prototype to return an int
instead of void.