proposal to separate netbsd 10 release from its predecessors which

build.rs

@@ -18,6 +18,7 @@ const ALLOWED_CFGS: &'static [&'static str] = &[
     "libc_const_extern_fn_unstable",
     "libc_deny_warnings",
     "libc_thread_local",
+    "netbsd10",
 ];
 
 // Extra values to allow for check-cfg.
@@ -62,6 +63,12 @@ fn main() {
         Some(_) | None => set_cfg("freebsd11"),
     }
 
+    match which_netbsd() {
+        // TODO: to update if there is a api breaking change
+        Some(10..=99) => set_cfg("netbsd10"),
+        Some(_) | None => (),
+    }
+
     match emcc_version_code() {
         Some(v) if (v >= 30142) => set_cfg("emscripten_new_stat_abi"),
         // Non-Emscripten or version < 3.1.42.
@@ -183,6 +190,21 @@ fn which_freebsd() -> Option<i32> {
     }
 }
 
+fn which_netbsd() -> Option<i32> {
+    let output = std::process::Command::new("uname").arg("-r").output().ok();
+    if output.is_none() {
+        return None;
+    }
+
+    let output = output.unwrap();
+    let stdout = String::from_utf8(output.stdout).ok().unwrap();
+
+    match &stdout {
+        s if s.starts_with("10") => Some(10),
+        _ => None,
+    }
+}
+
 fn emcc_version_code() -> Option<u64> {
     let output = std::process::Command::new("emcc")
         .arg("-dumpversion")

libc-test/build.rs

@@ -1044,6 +1044,13 @@ fn test_netbsd(target: &str) {
     assert!(target.contains("netbsd"));
     let mut cfg = ctest_cfg();
 
+    let netbsd_ver = which_netbsd();
+
+    match netbsd_ver {
+        Some(10..=99) => cfg.cfg("netbsd10", None),
+        _ => &mut cfg,
+    };
+
     cfg.flag("-Wno-deprecated-declarations");
     cfg.define("_NETBSD_SOURCE", Some("1"));
 
@@ -4539,6 +4546,21 @@ fn which_freebsd() -> Option<i32> {
     }
 }
 
+fn which_netbsd() -> Option<i32> {
+    let output = std::process::Command::new("uname").arg("-r").output().ok();
+    if output.is_none() {
+        return None;
+    }
+
+    let output = output.unwrap();
+    let stdout = String::from_utf8(output.stdout).ok().unwrap();
+
+    match &stdout {
+        s if s.starts_with("10") => Some(10),
+        _ => None,
+    }
+}
+
 fn test_haiku(target: &str) {
     assert!(target.contains("haiku"));
 

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

@@ -286,7 +286,10 @@ s! {
         pub flags: u32,
         pub fflags: u32,
         pub data: i64,
-        pub udata: ::intptr_t, /* FIXME: NetBSD 10.0 will finally have same layout as other BSD */
+        #[cfg(netbsd10)]
+        pub udata: *mut ::c_void,
+        #[cfg(not(netbsd10))]
+        pub udata: ::intptr_t,
     }
 
     pub struct dqblk {