IGNORE_ERRORS is not respected

For Developers
1

I'm trying to debug package compile failing by passing IGNORE_ERRORS=n to make env vars, but it doesn't seem respected:

IGNORE_ERRORS=n make package/feeds/<feed>/<pkg>/compile V=sc
...
make[2]: [Makefile:57: compile] Error 1 (ignored)
...
2

If you try to ignore the errors, it's IGNORE_ERRORS=1; on the contrary, if you want to disable this behaviour, it's IGNORE_ERRORS=0.

3

Still no difference, compiling from snapshot SDK:

$ IGNORE_ERRORS=0 make -j$((`nproc` + 1)) package/feeds/modemfeed/atinout/compile V=sc IGNORE_ERRORS=0
...
make[2]: [Makefile:57: compile] Error 1 (ignored)
...

Log:
http://ix.io/4bRg
I'm using this feed:

4

Hmm, it seems I have to enable the package in make menuconfig first.
I didn't see that clearly enough in the documentation