- incorporate label checking logic from pmloglabel/pmloglabel.c

- see existing src/pmlogsummary/pmlogcheck.c

- conditional checking from pmNewContext with PM_CONTEXT_ARCHIVE,
  based on an environment variable (or maybe even a type modifier
  to pmNewContext, in the flavor of PM_CTXFLAG_SECURE)

- consideration for repair
  (a) automatic
  (b) interactive