The previous commit fixed the problem of allowing apropos to not crash and
produce output even if the database is missing values for certain mandatory
fields, such as name, section etc. Normally we don't expect those values
to be missing in the database but in case of parsing errors it can happen.
However, the machine architecture is an optional field since not all man pages
are hardware specific so that should be allowed to be set to NULL if not
present in the database.
b0ca50fb4d