Auto merge of #3063 - devnexen:mimmutable_obsd, r=JohnTitor

adding mimmutable from openbsd (7.3)

Author: bors

libc-test/build.rs

@@ -534,6 +534,9 @@ fn test_openbsd(target: &str) {
             // futex() has volatile arguments, but that doesn't exist in Rust.
             "futex" => true,
 
+            // Available for openBSD 7.3
+            "mimmutable" => true,
+
             _ => false,
         }
     });

libc-test/semver/openbsd.txt

@@ -1091,6 +1091,7 @@ malloc_conceal
 memmem
 memrchr
 mfs_args
+mimmutable
 mincore
 mkdirat
 mkfifoat

src/unix/bsd/netbsdlike/openbsd/mod.rs

@@ -1888,6 +1888,8 @@ extern "C" {
         timeout: *const ::timespec,
         uaddr2: *mut u32,
     ) -> ::c_int;
+
+    pub fn mimmutable(addr: *mut ::c_void, len: ::size_t) -> ::c_int;
 }
 
 #[link(name = "execinfo")]