Auto merge of #45725 - alexcrichton:std-less-rand, r=dtolnay

Working towards a libc-less (wasm32) libstd

This is a series of commits I was able to extract from prepare to comiple libstd on a "bare libc-less" target, notably wasm32. The actual wasm32 bits I intend to send in a PR later, this is just some internal refactorings required for libstd to work with a `libc` that's empty and a few other assorted refactorings.

No functional change should be included in this PR for users of libstd, this is intended to just be internal refactorings.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/libstd/sys/unix/stdio.rs b/src/libstd/sys/unix/stdio.rs
index 7a8fe25d98e..e9b3d4affc7 100644
--- a/src/libstd/sys/unix/stdio.rs
+++ b/src/libstd/sys/unix/stdio.rs
@@ -70,5 +70,8 @@ impl io::Write for Stderr {
     }
 }
 
-pub const EBADF_ERR: i32 = ::libc::EBADF as i32;
+pub fn is_ebadf(err: &io::Error) -> bool {
+    err.raw_os_error() == Some(libc::EBADF as i32)
+}
+
 pub const STDIN_BUF_SIZE: usize = ::sys_common::io::DEFAULT_BUF_SIZE;