tdb: enforce hashing, via example hash in old rwlocks entry in header.
[ccan] / ccan / tap /
drwxr-xr-x   ..
-rw-r--r-- 1422 _info
-rw-r--r-- 9855 tap.3
-rw-r--r-- 8966 tap.c
-rw-r--r-- 8225 tap.h
drwxr-xr-x - test