libspatialite fails to build on netbsd-9

[Greg Troxel <gdt%lexort.com@localhost>]

checking for strerror... (cached) yes
checking for sqlite3_prepare_v2 in -lsqlite3... yes
checking for inflateInit_ in -lz... yes
checking for sqlite3_rtree_query_callback in -lsqlite3... no
configure: error: obsolete 'libsqlite3' (< v.3.8.5). please retry specifying: --disable-knn
*** Error code 1

I do have sqlite3-3.40.1 installed.

I built libspatialite-4.3.0anb19 on February 13 (my tree was out of date
probably).

This seems like fallout from the update to 5, and may be as simple as
needing an API requirement for sqlite3.