Yes! SDR is an amateur radio topic. Just because it's software defined doesn't mean it's any less a radio than any other ham radio.
However, there are questions which will obviously lie in a gray area, and which may be better solved elsewhere.
The example question, which asks about trying to compile an SDR program on a computer, isn't an Amateur Radio question. We won't solve it using Amateur Radio techniques and knowledge.
It is a question an Amateur Radio enthusiast might have, but it's not an Amateur Radio problem.
Still, I don't see a problem with allowing these problems - we're trying to build a community of Amateur Radio experts, and we do want SDR experts to hang out here.
So my vote would be to keep the question up, allow similar questions that primarily regard trying to get an Amateur Radio station on the air, even if it involves programming knowledge, and revisit the topic in a year or two.