Source section is not optional

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Moved distinction for assembling primitives into mgenc

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Updated core-lib

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Fix left shift semantics

ovfcheck(<<) works only for values smaller than LONG_BIT

Signed-off-by: Stefan Marr <git@stefan-marr.de>