Sometimes a C codebase might have the odd file written in Assembly. We should force the use of Clang as the assembly compiler for these cases (which it is perfectly capable of doing), and make sure we pass on the WASI compiler triple the same way we do for C and C++.
* Update how wasi-sdk uses cmake
Change `CMAKE_SYSTEM_NAME` to `WASI`, use a `CMAKE_MODULE_PATH`,
remove `CACHE` usage, and fix the compiler autodetection code so that
the "compiler works" hacks are no longer needed, following the advice in
[this comment](https://gitlab.kitware.com/cmake/cmake/-/issues/19223#note_567327).
This is hopefully a step towards re-submitting WASI support to upstream cmake.
* Add --sysroot to compiler-rt's C flags.
This ensures that it finds the built sysroot when testing whether the C
compiler works.
* Fixes.
* Use the just-built ar rather than the host ar.
* Use -DCMAKE_C_COMPILER_WORKS=ON instead of stubbing out archive files.
* Use -DCMAKE_CXX_COMPILER_WORKS=ON too.
* Restore the `--sysroot` argument when building compiler-rt.
compiler-rt depends on some libc headers, so it needs a sysroot.
* Add sysroot arguments for libc++ and libc++abi too.
* Also set CMAKE_AR.
It appears with the removal of the AR checks cmake is no longer
autodetecting CMAKE_AR, so set it explicitly.
* Remove --no-threads from wasi-sdk.cmake.
It was added to work around this bug:
https://bugs.llvm.org/show_bug.cgi?id=41508
which was fixed in LLVM 9.0.
* Remove LLVM 8.0 workarounds.
* Make build work on Windows
* re-enable windows build workflow
* fix make check
* fix tar_from_installation.sh and dist target
* Review fixups
* No -j4 on Windows
* Get rid of -j4 everywhere in Makefile
This renames /opt/wasi/share/sysroot to /opt/wasi/share/wasi-sysroot.
If the user selects an alternate prefix, this allows wasi-sysroot to
coexist with other packages with less risk of namespace collision. For
example, if the user uses a prefix of /usr/local, this avoids using
/usr/local/share/sysroot, which is fairly generic, and uses
/usr/local/share/wasi-sysroot, which more clearly indicates its purpose.