glibc is
the standard for C libraries to follow on Linux.
In this particular case, mkstemp() is not a viable replacement for mkostemp(). A proper fix is to provide mkostemp() in uClibc, or to compile with a shim that provides it.
Arguing over whether including the shim in Systemd would be acceptable would be a different matter, but parts of the patches as presented were flat out broken.
And the Linux kernel is not starting to depend on systemd or the others. The Linux kernel is moving towards demanding a single cgroups writer, and at the moment Systemd is the main contender in that space.
That Systemd is depending on Linux is unsurprising, given that they stated from the outset exactly that they were unwilling to pay the price of trying to implement generic abstractions rather than taking full advantage of the capabilities Linux offers. You may of course disagree with that decision, but frankly, for a lot of us getting a better init system for the OS we use is more important than getting some idealised variation that the BSD's could use too.
> an architecture that promotes this very lock-in to begin with.
The "architecture that promotes this very lock-in" in this case is "provide functionality that people want so badly they're prepared to introduce dependencies on systemd".
At some points enough is enough, and sub-optimal advances still end up getting adopted because the alternatives are worse. Systemd falls squarely in that category: I agree it'd be nicer if it was presented and introduced in nice small digestible separate chunks with well defined, stadardised APIs so that people could be confident in the ability to replace the various APIs. But if the alternative is remaining with the alternatives? I'll pick Systemd warts and all.
Looking at posts from the Gnome people, the original intent appears to have been to provide a narrow logind shim exactly to make it easier to replace logind/systemd with something else. If someone feels strongly enough to come up with a viable shim or an alternative API that can talk to both systemd and other systems reliably, then I'd expect Gnome to be all over that exactly because they will otherwise have the headache of how to continue to support other platforms.
The problem is that Gnome already for a long time have dependend on expectations of the user session management that ConsoleKit on top of other init systems have been unable to properly meet, so Gnome has in many scenarios been subtly broken for a long time.