See: https://github.com/tinygo-org/tinygo/issues/4314
The os package isn't particularly useful on wasm-unknown, but just like
on baremetal systems it's imported by a lot of packages so it should at
least be possible to import this package.
This eliminates the 'wasi' build tag in favor of 'GOOS=wasip1', introduced in Go 1.21.
For backwards compatablity, -target=wasi is a synonym for -target=wasip1.
This adds true GOOS=wasip1 support in addition to our existing
-target=wasi support. The old support for WASI isn't removed, but should
be treated as deprecated and will likely be removed eventually to reduce
the test burden.
Ayke van Laethem
Randy Reddig
Yurii Soldak
Dan Kegel