Auto merge of #2628 - devnexen:netbsd_prot_mprotect, r=Amanieu

netbsd add PROT_MPROTECT macros.

libc-test/semver/netbsd.txt

@@ -765,6 +765,7 @@ POSIX_SPAWN_SETSCHEDPARAM
 POSIX_SPAWN_SETSCHEDULER
 POSIX_SPAWN_SETSIGDEP
 POSIX_SPAWN_SETSIGMASK
+PROT_MPROTECT
 PTHREAD_CREATE_DETACHED
 PTHREAD_CREATE_JOINABLE
 PTHREAD_MUTEX_DEFAULT

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

@@ -2105,6 +2105,14 @@ f! {
         };
         ::mem::size_of::<sockcred>() + ::mem::size_of::<::gid_t>() * ngrps
     }
+
+    pub fn PROT_MPROTECT(x: ::c_int) -> ::c_int {
+        x << 3
+    }
+
+    pub fn PROT_MPROTECT_EXTRACT(x: ::c_int) -> ::c_int {
+        (x >> 3) & 0x7
+    }
 }
 
 safe_f! {