Added MSG_WAITFORONE flag to MsgFlags (#2014)

Author: stevenengler

CHANGELOG.md

@@ -29,6 +29,9 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - Removed `flock` from `::nix::fcntl` on Solaris. ([#2082](https://github.com/nix-rust/nix/pull/2082))
 - Use I/O safety with `copy_file_range`, and expose it on FreeBSD.
   (#[1906](https://github.com/nix-rust/nix/pull/1906))
+- Added `MSG_WAITFORONE` to `MsgFlags` on Android, Fuchsia, Linux, NetBSD,
+  FreeBSD, OpenBSD, and Solaris.
+  ([#2014](https://github.com/nix-rust/nix/pull/2014))
 
 ### Changed
 

src/sys/socket/mod.rs

@@ -374,6 +374,17 @@ libc_bitflags! {
                   target_os = "solaris"))]
         #[cfg_attr(docsrs, doc(cfg(all())))]
         MSG_NOSIGNAL;
+        /// Turns on [`MSG_DONTWAIT`] after the first message has been received (only for
+        /// `recvmmsg()`).
+        #[cfg(any(target_os = "android",
+                  target_os = "fuchsia",
+                  target_os = "linux",
+                  target_os = "netbsd",
+                  target_os = "freebsd",
+                  target_os = "openbsd",
+                  target_os = "solaris"))]
+        #[cfg_attr(docsrs, doc(cfg(all())))]
+        MSG_WAITFORONE;
     }
 }