[wasi-common]: add armv7 support to wasi-common (#1269)

* Add armv7 support to wasi-common

This commit enables `target_pointer_width = 32` compatibility for
`wasi-common` (and by transitivity, any crate found inside, e.g., `yanix`).
I've also added a simplistic (bare minimum) check to our CI to ensure
that `wasi-common` cross-compiles to `armv7-unknown-gnueabihf` fine.
While here, I've done the same for `wasm32-unknown-emscripten`.

* Clean arch-specific impls + reuse libc consts

* Make SeekLoc::from_raw platform independent

* Collapse CI cc jobs into one

crates/wasi-common/yanix/src/sys/linux/filetime.rs

@@ -6,9 +6,6 @@ use std::fs::File;
 use std::io::Result;
 use std::sync::atomic::{AtomicBool, Ordering::Relaxed};
 
-pub(crate) const UTIME_NOW: i64 = 1_073_741_823;
-pub(crate) const UTIME_OMIT: i64 = 1_073_741_822;
-
 /// Wrapper for `utimensat` syscall, however, with an added twist such that `utimensat` symbol
 /// is firstly resolved (i.e., we check whether it exists on the host), and only used if that is
 /// the case. Otherwise, the syscall resorts to a less accurate `utimesat` emulated syscall.

crates/wasi-common/yanix/src/sys/linux/mod.rs

@@ -3,13 +3,3 @@ pub(crate) mod fadvise;
 pub(crate) mod file;
 pub(crate) mod filetime;
 pub(crate) mod utimesat;
-
-use crate::dir::SeekLoc;
-use std::io::Result;
-
-impl SeekLoc {
-    pub unsafe fn from_raw(loc: i64) -> Result<Self> {
-        let loc = loc.into();
-        Ok(Self(loc))
-    }
-}

crates/wasi-common/yanix/src/sys/linux/utimesat.rs

@@ -1,4 +1,5 @@
 use crate::filetime::FileTime;
+use crate::filetime::FileTimeExt;
 use crate::from_success_code;
 use std::fs;
 use std::io::Result;
@@ -26,19 +27,16 @@ pub fn utimesat(
     let fd = unsafe { libc::openat(dirfd.as_raw_fd(), p.as_ptr(), flags) };
     let f = unsafe { fs::File::from_raw_fd(fd) };
     let (atime, mtime) = get_times(atime, mtime, || f.metadata().map_err(Into::into))?;
-    let times = [to_timeval(atime), to_timeval(mtime)];
+    let times = [to_timeval(atime)?, to_timeval(mtime)?];
     from_success_code(unsafe { libc::futimes(f.as_raw_fd(), times.as_ptr()) })
 }
 
-/// Converts `filetime::FileTime` to `libc::timeval`. This function was taken directly from
-/// [filetime] crate.
-///
-/// [filetime]: https://github.com/alexcrichton/filetime/blob/master/src/unix/utimes.rs#L93
-fn to_timeval(ft: filetime::FileTime) -> libc::timeval {
-    libc::timeval {
-        tv_sec: ft.seconds(),
-        tv_usec: (ft.nanoseconds() / 1000) as libc::suseconds_t,
-    }
+/// Converts `filetime::FileTime` to `libc::timeval`.
+fn to_timeval(ft: filetime::FileTime) -> Result<libc::timeval> {
+    Ok(libc::timeval {
+        tv_sec: ft.seconds_()?,
+        tv_usec: (ft.nanoseconds_() / 1000) as libc::suseconds_t,
+    })
 }
 
 /// For a provided pair of access and modified `FileTime`s, converts the input to