I'm not sure if/when I replied to this post... BUT IT ROCKS!!!
This implementation is only slightly different than the CSV version supplied with the SQLITE3 source and frankly I use them both. What's awesome about this is that I've been able to load the extensions into my golang projects too. In fact my use-case loads a zipcode table with lat/long and I use another extension to compute the estimated, as the crow flies, distance between two zipcodes.
But one thing is missing from the mention. If you use chroot, like I did in both linux, freebsd and OpenBSD... you have to remember to copy the dependent libs from the root OS to the chroot in the same/similar path tree.
(hope that makes sense)
I compiled my vsv.c and moved it to the lib/ folder of my chroot dir.
I ran this to locate the DEPS
```
$ ldd lib/vsv.so
lib/vsv.so:
Start End Type Open Ref GrpRef Name
00000f929a569000 00000f929a572000 dlib 1 0 0 /home/rbucker/src/bppdash/lib/vsv.so
00000f9323bc1000 00000f9323bf1000 rlib 0 1 0 /usr/lib/libm.so.10.1
```
I had to create 'usr/lib' and then copy '/usr/lib/libm.so.10.1' to 'usr/lib'.
then I was able to chroot and then load the extension.