> Like some I would guess who bother to try and build -current, I
> think I've seen at least one person "hint" at the existing problem
> that is plaguing -current on NetBSD/vax the past few months.
> 
[...]
> make: Could not fork: Cannot allocate memory
> 
This is because make allocates more memory than DFLDSIZ; currently 16MB.
If you do "unlimit datasize" before typing make it works better.

The main problem is that increasing MAXDSIZ to more than currently 24MB
steals so much memory that the kernel won't boot on low-memory machines.
If you have much memory in your machine, compile a new kernel with 
"options DFLDSIZ="(48*1024*1024)"
"options MAXDSIZ="(64*1024*1024)"

or something similar.

-- Ragge