[PATCH] Teach Catalog.pm how many attributes there should be per DATA() line

Fixes a build issue I ran into while adding some columns to system tables:

Throws a build error if we encounter a different number of fields in a
DATA() line than we expect for the catalog in question.

Previously, it was possible to silently ignore any mismatches at build
time which could result in symbol undefined errors at link time. Now
we stop and identify the infringing line as soon as we encounter it,
which greatly speeds up the debugging process.