mman add MAP_CONCEAL mmap flag for openbsd

Author: devnexen

CHANGELOG.md

@@ -46,6 +46,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
   (#[1525](https://github.com/nix-rust/nix/pull/1525))
 - Added `MAP_ALIGNED_SUPER` mmap flag for freebsd.
   (#[1522](https://github.com/nix-rust/nix/pull/1522))
+- Added `MAP_CONCEAL` mmap flag for openbsd.
+  (#[1531](https://github.com/nix-rust/nix/pull/1531))
 
 ### Changed
 

src/sys/mman.rs

@@ -143,6 +143,9 @@ libc_bitflags!{
         /// Allows to use large pages, underlying alignment based on size.
         #[cfg(target_os = "freesd")]
         MAP_ALIGNED_SUPER;
+        /// Pages will be discarded in the core dumps.
+        #[cfg(target_os = "openbsd")]
+        MAP_CONCEAL;
     }
 }