tally: don't add extra bucket unless buckets == 0
[ccan] / ccan / tally /
drwxr-xr-x   ..
-rw-r--r-- 1313 _info
-rw-r--r-- 11985 tally.c
-rw-r--r-- 3254 tally.h
drwxr-xr-x - test