the pathnames prefixed with /dev/null/ are guaranteed never to be valid. the previous use of /dev/null alone was mildly dangerous in that bad software might attempt to unlink the name when it found a non-regular file there and create a new file.
one file was reusing another file's macro name, and many had inconsistent underscores and application of SYS prefix, etc. patch by Szabolcs Nagy (nsz)