backend_sources += files(
  'appendinfo.c',
  'clauses.c',
  'inherit.c',
  'joininfo.c',
  'orclauses.c',
  'paramassign.c',
  'pathnode.c',
  'placeholder.c',
  'plancat.c',
  'predtest.c',
  'relnode.c',
  'restrictinfo.c',
  'tlist.c',
  'var.c',
)