To allow non-POSIX platforms such as Windows to support WASI libc
filesystem functionality, create a set of wrapper functions which provide a
platform-agnostic interface to interact with the host filesystem. For now,
the Windows implementation is stubbed but this will be implemented
properly in a future PR. There are no functional changes in this change,
just a reorganization of code to move any direct POSIX references out of
posix.c in the libc implementation into posix_file.c under the shared
POSIX sources.
See https://github.com/bytecodealliance/wasm-micro-runtime/issues/2495 for a
more detailed overview of the plan to port the WASI libc filesystem to Windows.
This PR adds the Cosmopolitan Libc platform enabling compatibility with multiple
x86_64 operating systems with the same binary. The platform is similar to the
Linux platform, but for now only x86_64 with interpreter modes are supported.
The only major change to the core is `posix.c/convert_errno()` was rewritten to use
a switch statement. With Cosmopolitan errno values depend on the currently
running operating system, and so they are non-constant and cannot be used in array
designators. However, the `cosmocc` compiler allows non-constant case labels in
switch statements, enabling the new version.
And updated wamr-test-suites script to add `-j <platform>` option. The spec tests
can be ran via `CC=cosmocc ./test_wamr.sh -j cosmopolitan -t classic-interp`
or `CC=cosmocc ./test_wamr.sh -j cosmopolitan -t fast-interp`.
