There's a PATH_LOCALE setting in one of the *ENV that should get similar treatment- I would suspect the variable is pretty specific to our libc (and Dragonfly, maybe Illumos and macOS), but probably better to be clear.

I'd also be supportive of your other proposal to avoid it if DESTDIR != /, though I don't know if you dismissed that idea entirely. I don't feel strongly about it...

i went through a couple of approaches here; i think ideally we should disable this entire feature, even on FreeBSD, when we aren't doing a live installworld, but that's a larger and more risky change... this is the least invasive change that fixes the Linux build in the mean time.