Can't generate a new event base number

[i5okie]

$ mos version                                                                                                                                          jonas 2.3.8
The Mongoose OS command line tool
Version: 201911162313
Build ID: 20191121-033810/2.16.0-3-g51708b2-master
Update channel: latest

build error:

/mongoose-os/include/mgos_event.h:39:34: error: expected declaration specifiers or '...' before '(' token
 #define MGOS_EVENT_BASE(a, b, c) ((a) << 24 | (b) << 16 | (c) << 8)
                                  ^

I've been trying to generate a new event base number, and keep running into this.
Trying to do #define MY_EVENT_BASE (1177563136) results in the same error, just pointing to the first opening bracket here.