FreeBSD's mkstemp sets the temporary file's permissions to 600, and has ever
since mkstemp was added in 1987. Coverity's warning is still relevant for
portable programs since OpenGroup does not require that behavior, and POSIX
didn't until 2008. But none of these programs are portable.
umask(2) should always be used prior to mkstemp(3) so the temporary file
won't be created with insecure permissions.
Reported by: Coverity
CID: 1331605 1347173 1375366 1339800 1331604 1296056 1296060
CID: 1296057 1296062
MFC after: 2 weeks