g-ir-scanner fails to build on older MacOS 10.13
g-ir-scanner stops with assertion failed: ...vtable.unit_get_identifier != NULL
On MacOS 10.13 High Sierra circa 2017, the earliest that Apple still supports. A Macports build using a Portfile similar to the Gimp official one. This issue does not affect builds on later versions of MacOS. On a 12 year old computer, Apple does not support with a newer OS.
A temporary workaround is to compile with -Db_sanitize=address, which skips GIR step. Suitable only for limited testing.
I don't understand the g-ir-scanner, why it is executing a library. Anyway, looking at the Gimp code, it seems like a call to gimp_unit_init is not made in a timely fashion. That is what initializes the vtable. I don't understand the code for "unit" either.
Probably not worth pursuing.