Git 2.20.4

1. 8c84ae6 oidset: uninline oidset_init() by René Scharfe · 7 years ago
2. 8b2f8cb oidset: use khash by René Scharfe · 7 years ago
3. c3a9ad3 oidset: add iterator methods to oidset by Jeff Hostetler · 8 years ago
4. 9e6fabde oidmap: map with OID as key by Jonathan Tan · 8 years ago
5. 7663cdc hashmap.h: compare function has access to a data field by Stefan Beller · 8 years ago
6. 29c2bd5 add oidset API by Jeff King · 9 years ago