This commit disables building documentation on cross-compiled compilers, for
example ARM/MIPS/PowerPC/etc. Currently I believe we're not getting much use out
of these documentation artifacts and they often take 10-15 minutes total to
build as it requires building rustdoc/rustbook and then also generating all the
documentation, especially for the reference and the book itself.
In an effort to cut down on the amount of work that we're doing on dist CI
builders in light of recent timeouts this was some relatively low hanging fruit
to cut which in theory won't have much impact on the ecosystem in the hopes that
the documentation isn't used too heavily anyway.
While initial analysis in #48827 showed only shaving 5 minutes off local builds
the same 5 minute conclusion was drawn from #48826 which ended up having nearly
a half-hour impact on the bots. In that sense I'm hoping that we can land this
and test out what happens on CI to see how it affects timing.
Note that all tier 1 platforms, Windows, Mac, and Linux, will continue to
generate documentation.
These arguments are passed to the relevant x.py invocation in all cases
anyway. As such, there is no need to separately configure them. x.py
will ignore the configuration when they are passed on the command line
anyway.
On some systems, the bash command could be available in another
directory than /bin. As such, to offer an env shebang is more
convenient.
This make sense even for docker scripts, as you can use Docker
on FreeBSD or SmartOS for example.
Now that the final bug fixes have been merged into sccache we can start
leveraging sccache on the MSVC builders on AppVeyor instead of relying on the
ad-hoc caching strategy of trigger files and whatnot.
I've tracked down what I believe is the last spurious sccache failure on #40240
to behavior in mio (carllerche/mio#583), and this commit updates the binaries to
a version which has that fix incorporated.
Previously we would use one builder on Travis to produce two sets of host
compilers for two different targets. Unfortunately though we've recently
increased how much we're building for each target so this is starting to take
unnecessarily long (#40804). This commit splits the dist builders in two by
ensuring that we only dist one target on each builder, which should take a much
shorter amount of time. This should also unblock other work such as landing the
RLS (#40584).
