backend_sources += files(
  'heapam.c',
  'heapam_handler.c',
  'heapam_visibility.c',
  'heaptoast.c',
  'hio.c',
  'pruneheap.c',
  'rewriteheap.c',
  'vacuumlazy.c',
  'visibilitymap.c',
)