Until the first instance of a friend snitching to an author AND the author caring and suing the gifter the answer is a solid yes. Technically the terms require it, technically you probably broke 15 laws before breakfast especially if you assume officers won't give the benefit of the doubt in cases where they have discretion. Either way, given that you have access to the source how difficult is it to toss it in?
The real case for this was a bit more complex. It wasn't a friend compiling it, it was a Linux distribution. Compile the code and ship packages. Definitely useful, yes? Except that according to the GPL, the recipient of the code is allowed to demand the source code and the distribution in question hadn't kept a copy and upstream had gone away. They had to scrabble to find a copy from a mirror, or face legal action. As a result, distributions that provide binary packages now also mirror the source code and keep it around for a long time. That adds cost to everyone that ships binary packages of GPL'd code. GPLv3 explicitly addressed this because it was a real concern that was costing money.
Your other cases are all about trying to find loophole conditions under which you can steal the code without sharing code back under the same terms. Yes, if you start trying to find ways to dodge sharing back code you'll start running into the legal clauses designed to make this difficult since it is the entire point of the license.
Why is it fine for me to ship a binary-only program that's tightly coupled to a GPL'd library via a pipe, but not when it's via linkage? The GNU GPL FAQ specifically makes this distinction, but it's an entirely arbitrary one based on a specific execution model.