The actor directives (.constructor, .destructor, .interruptor, and .condes)
can't handle a symbol that's already exported.
The relevant code does the checks in the wrong order.
For example, the following correct snippet does not assemble:
.export C
C: .constructor C, 5
The assembler outputs: test.s:2: Error: Address size mismatch for symbol 'C'
Exchanging both lines makes it work.
This fixes#1647; the patch is provided by 'kugelfuhr' and taken from there.
364e72921c