Adds TemporaryDirectoryWinProof which calls windows_proof_rmtree() on
error.
Use instead of hacky error handling (which might shadow other OSError)
in Compiler.compile().
Since the current approach of demoting to the nearest C standard *might*
work, but might not. For projects like Glib that detect which standard
is used and fall back this is fine. For projects like libdrm that only
work with gnu standards, this wont. We're nog tusing a warning because
this shouldn't be fatal if --meson-fatal-warnings is used. Also demote a
similar message in IntelCl from warning to log.
And then update the choices in each leaf class. This way we don't end up
with another case where we implicitly allow an invalid standard to be
set on a compiler that doesn't have a 'std' setting currently.
As far as I can Tell, rust just handles this for us (it's always worked
with no special arguments from us). However, since we're going to add
support for base options for rust, we need to add the method.
When TemporaryDirectory() cleans up on __exit__ it sometimes throws
OSError noting that the dir isn't empty. This happens after the
first yield in this generator and leads to the exception being handled
which leads to a second yield.
contextlib.contextmanager() fails then since the function it wraps is only
allowed to yield once.
Fix this by not yielding again in the error case.
Fixes#7947
Using the std option, so now `rust_std=..` will work. I've chosen to use
"std" even though rust calls these "editions", as meson refers to
language versions as "standards", which makes meson feel more uniform,
and be less surprising.
Fixes: #5100
It is much easier to not try to parse options into complicated
structures until we actually collected all options: machine files,
command line, project()'s default_options, environment.
The implementation of the link variant was what should have been the
compiler variant, and there was no valid compiler variant, which meant
it was getting C code.
This abstraction is really useful, and most compilers could use it
(including D). It also will allow the Gnu mixins to work properly
without the CLikeCompiler in their mro.
