* Move `raise` code to be behind an autoconf check
This moves the call to `raise` behind a `HAVE_RAISE` autoconf check,
in addition to `__wasm__`. This is intended to help porting to
other platforms that don't support `raise` (e.g. modern game consoles).
* Add autoconf check for `sysconf`
Only try to invoke `sysconf` if the target platform supports it, and
don't warn about unknown page size if `PAGE_SIZE` was defined. Add an
include for `sys/param.h` to increase likelihood of finding `PAGE_SIZE`.
This is intended to help porting to other platforms that don't support
`sysconf` (e.g. modern game consoles) that have a fixed hardware page
size.
* Don't try to use raise & sysconf in a WASI environment
Co-authored-by: Frank Denis <124872+jedisct1@users.noreply.github.com>