[boilerpate] Move target definition to backends.

By moving the backend target definition out of the massive amlagamated
block in cairo-boilerplate.c and into each of the
cairo-boilerplate-backend.c, we make it much easier to add new targets as
the information need only be entered in a single file and not scattered
across three. However, updating the target interface means trawling across
all the files -- except given that I found it difficult maintaining the
single massive array I do not see this as an increase in the maintenance
burden.

0 files changed, 0 insertions, 0 deletions