- `func Load() (ok bool, err error)` to ease the integration in
dd-trace-go so that we can distinguish the different possible error
cases:
- Panic errors that must be used to gracefully abort the caller and
prevent it from continuing. Such errors are represented by the new
`PanicError` error type.
- Unsupported target OS and/or architecture, which must be handled as an
informative error, is worth logging to the user, and prevents the caller
from continuing. This error is represented by the new
`UnsupportedTarget` error type.
- Every other unexpected error that can possible happen is returned
as-is, but `ok` is `false`, so that the caller knows it cannot use the
package.
- Informative errors, about internal non-critical failures, can also
happen (eg. if os.Remove fails removing the temporary files), and are
returned as-is, but with `ok` being `true` so that the caller can log
the error and continue its startup.
- The dd-trace-go integration of this PR can be found here
DataDog/dd-trace-go#2090
- Note that `Health()` has been kept for the sake of simplicity
health-checking cases such as in the tests, where it returns the
`Load()` error only if `ok` is false, meaning that go-libddwaf is not
healthy.
- Simplified build tags, removed everywhere it was possible, down to
purego which isn't properly stubbed for unsupported targets and which we
stub ourselves at our level in the new `waf_dl_unsupported.go` file.

---------

Co-authored-by: Eliott Bouhana <[email protected]>
Co-authored-by: François Mazeau <[email protected]>