package/luajit: disable for static build

luajit requires dlopen().

Fixes:
http://autobuild.buildroot.net/results/20d/20dfb10198f3688f92208591960192ca08280987/
http://autobuild.buildroot.net/results/c3c/c3cfdf8dfb315bf64caa9ed0f362016111fd93ac/
http://autobuild.buildroot.net/results/8cb/8cbf6207ecf7b254aeccd9ec5c07376a044e1f8f/



[Thomas: propagate the new dependency to the sysdig package, which
selects luajit.]

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>