I'm looking for some help installing a tape drive under NetBSD 1.0. This
   is what dmesg returns: 

   bt0 targ 1 lun 0: <WangDAT Model 3100 02.2> SCSI2 sequential removable 
   No matching driver. 

   ...and I've found a reference to a Wangdat 1300 in /usr/src/sys/scsi/st.c

   What should I do to get the proper device compiled into the kernel?

It sounds like you built a custom kernel with no `st' driver (or one
not configured correctly).