all: Add package runtimeos for runtime.GOOS comparisons
I grew tired of hand written string comparisons. This adds generated
constants for the GOOS values, and predefined Is$OS constants that can
be iffed on. In a couple of places I rewrote trivial switch:es to if:s,
and added Illumos where we checked for Solaris (because they are
effectively the same, and if we're going to target one of them that
would be Illumos...).
I'm working through linter complaints, these are some fixes. Broad
categories:
1) Ignore errors where we can ignore errors: add "_ = ..." construct.
you can argue that this is annoying noise, but apart from silencing the
linter it *does* serve the purpose of highlighting that an error is
being ignored. I think this is OK, because the linter highlighted some
error cases I wasn't aware of (starting CPU profiles, for example).
2) Untyped constants where we though we had set the type.
3) A real bug where we ineffectually assigned to a shadowed err.
4) Some dead code removed.
There'll be more of these, because not all packages are fixed, but the
diff was already large enough.
This removes the special handling of minor versions as major when the
actual major is zero, and adds the special case that upgrades from 0.x
to 1.x are considered minor. 0.x to 2.x or 1.x to 2.x etc are still
considered major.
GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4226
New signature is the HMAC of archive name (which includes the release
version and architecture) plus the contents of the binary. This is
expected in a new file "release.sig" which may be present in a
subdirectory. The new release tools put this in [.]metadata/release.sig.
GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3043
