mandb: Fully reorganize databases

This allows us to produce bitwise-identical databases regardless of the
order in which pages were scanned (at least with GDBM).
`gdbm_reorganize` isn't enough for this, probably because entries end up
in different positions in hash buckets depending on insertion order; but
reading in the entire database and writing it back out in sorted order
seems to do the job with negligible cost.

Fixes Debian bug #1010957.

* src/mandb.c (reorganize): New function: read all the items from a
database in sorted order and write them back out.
(mandb): Stop calling `MYDBM_REORG`, which saved space after deletions
but didn't help with reproducibility.
(process_manpath): Call `reorganize` if any changes were made to a
database.
* libdb/mydbm.h (MYDBM_REORG): Remove macro.
* NEWS.md: Document this.

1 files changed, 3 insertions, 0 deletions

diff --git a/NEWS.md b/NEWS.md
index 72fb1f0c..970336a8 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -26,6 +26,9 @@ Improvements:
    database.
  * Extend rules for when to replace one database entry with another,
    producing more stable behaviour.
+ * Fully reorganize databases after writing them, allowing the reproduction
+   of bitwise-identical databases regardless of scan order (at least with
+   GDBM).
 
 man-db 2.10.2 (17 March 2022)
 =============================