https://github.com/inaturalist/inaturalist/wiki/Development-Setup-Guide might be out of date. I'm trying to follow it on an M1 MacBook with 15.3.1 and I can get as far as the step

CFLAGS="-Wno-error=implicit-function-declaration" rbenv install $(cat .ruby-version)

However that seems to die in the linker when building Ruby 3.0.4:

compiling set_len.c
linking shared-object -test-/string.bundle
1 warning generated.
linking shared-object date_core.bundle
make: *** [build-ext] Error 2
++ return 2

I'm trying to figure this out, but if anyone happens to know what else is needed, please comment here and edit the wiki. Thanks.