[wasi-common] Log string representation of WASI errno at the trace level (#760)

* Log str repr of WASI errno at trace level

This commit refactors `Error` enum, and adds logging of the WASI
errno string representation at the trace level. Now, when tracing
WASI syscalls, we will be greeted with a nicely formatted errno
value after each syscall:

```
path_open(...)
     | *fd=5
     | errno=ESUCCESS
```

This commit gets rid of `errno_from_nix`, `errno_from_win` and
`errno_from_host` helper fns in favour of direct `From` implementations
for the relevant types such as `yanix::Errno` and `winx::winerror::WinError`.
`errno_from_host` is replaced by a trait `FromRawOsError`.

* Back port changes to snapshot0

* Fix indentation in logs

crates/wasi-common/src/macros.rs

@@ -2,12 +2,12 @@ macro_rules! hostcalls {
     ($(pub unsafe fn $name:ident($($arg:ident: $ty:ty,)*) -> $ret:ty;)*) => ($(
             #[wasi_common_cbindgen::wasi_common_cbindgen]
             pub unsafe fn $name($($arg: $ty,)*) -> $ret {
-                let ret = match hostcalls_impl::$name($($arg,)*) {
-                    Ok(()) => wasi::__WASI_ERRNO_SUCCESS,
-                    Err(e) => e.as_wasi_errno(),
-                };
-
-                ret
+                let ret = crate::hostcalls_impl::$name($($arg,)*)
+                    .err()
+                    .unwrap_or(crate::Error::ESUCCESS)
+                    .as_wasi_error();
+                log::trace!("     | errno={}", ret);
+                ret.as_raw_errno()
             }
     )*)
 }
@@ -18,12 +18,12 @@ macro_rules! hostcalls_old {
     ($(pub unsafe fn $name:ident($($arg:ident: $ty:ty,)*) -> $ret:ty;)*) => ($(
             #[wasi_common_cbindgen::wasi_common_cbindgen_old]
             pub unsafe fn $name($($arg: $ty,)*) -> $ret {
-                let ret = match hostcalls_impl::$name($($arg,)*) {
-                    Ok(()) => wasi::__WASI_ERRNO_SUCCESS,
-                    Err(e) => e.as_wasi_errno(),
-                };
-
-                ret
+                let ret = crate::old::snapshot_0::hostcalls_impl::$name($($arg,)*)
+                    .err()
+                    .unwrap_or(crate::old::snapshot_0::Error::ESUCCESS)
+                    .as_wasi_error();
+                log::trace!("     | errno={}", ret);
+                ret.as_raw_errno()
             }
     )*)
 }