lensfun: increase verbosity of `make` to ease debugging

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Update lensfun URL in test file

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
lensfun-test: use correct #include style and don't return negative exit code

Signed-off-by: Timothy Gu <timothygu99@gmail.com>