canfestival: disable static build

canfestival doesn't really support static build. The configure script accepts
the --disable-dll parameter that should in theory allow a static build. In
practice this options is not well tested, as it causes the build to fails in
various places.

Fixes:
http://autobuild.buildroot.net/results/29f/29fd3e550937f48e2270149a3d44cfb8bcf5c16a/



Cc: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>