Auto merge of #1325 - sunfishcode:wasi-more-libc, r=alexcrichton

Add more WASI libc bindings

This picks up #1321, adding more WASI libc bindings, adding several more fixes. In particular, `cargo test --all` including libc-test now builds successfully.

libc-test/build.rs

@@ -1875,17 +1875,28 @@ fn test_wasi(target: &str) {
     cfg.define("_GNU_SOURCE", None);
 
     headers! { cfg:
+        "ctype.h",
+        "dirent.h",
         "errno.h",
         "fcntl.h",
         "limits.h",
         "locale.h",
         "malloc.h",
+        "poll.h",
+        "stdbool.h",
         "stddef.h",
         "stdint.h",
         "stdio.h",
         "stdlib.h",
+        "string.h",
+        "sys/resource.h",
+        "sys/select.h",
+        "sys/socket.h",
         "sys/stat.h",
+        "sys/times.h",
         "sys/types.h",
+        "sys/uio.h",
+        "sys/utsname.h",
         "time.h",
         "unistd.h",
         "wasi/core.h",
@@ -1895,7 +1906,7 @@ fn test_wasi(target: &str) {
     }
 
     cfg.type_name(move |ty, is_struct, is_union| match ty {
-        "FILE" => ty.to_string(),
+        "FILE" | "fd_set" | "DIR" => ty.to_string(),
         t if is_union => format!("union {}", t),
         t if t.starts_with("__wasi") && t.ends_with("_u") => {
             format!("union {}", t)
@@ -1920,5 +1931,9 @@ fn test_wasi(target: &str) {
     // import the same thing but have different function pointers
     cfg.skip_fn_ptrcheck(|f| f.starts_with("__wasi"));
 
+    // d_name is declared as a flexible array in WASI libc, so it
+    // doesn't support sizeof.
+    cfg.skip_field(|s, field| s == "dirent" && field == "d_name");
+
     cfg.generate("../src/lib.rs", "main.rs");
 }

src/lib.rs

@@ -112,7 +112,7 @@ cfg_if! {
     } else if #[cfg(all(target_env = "sgx", target_vendor = "fortanix"))] {
         mod sgx;
         pub use sgx::*;
-    } else if #[cfg(target_env = "wasi")] {
+    } else if #[cfg(any(target_env = "wasi", target_os = "wasi"))] {
         mod wasi;
         pub use wasi::*;
     } else {