See pull request 151 for my proposed fix.
The template SQL for creating geometry type triggers is missing a closing parenthesis for both the INSERT and the UPDATE trigger definitions.
Implementers of Annex M have noticed this and have added the missing parentheses. See libspatialite (as of version 4.3.0a) for an example. They have implemented Annex M in src/geopackage/gpkg_add_geometry_triggers.c