For VxWorks:

fix building errors
use wr-c++ as linker

library/std/src/sys/vxworks/fd.rs

@@ -53,7 +53,7 @@ pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
     }
 
     #[inline]
-    fn is_read_vectored(&self) -> bool {
+    pub fn is_read_vectored(&self) -> bool {
         true
     }
 

library/std/src/sys/vxworks/process/process_common.rs

@@ -351,8 +351,7 @@ pub fn new(status: c_int) -> ExitStatus {
     }
 
     fn exited(&self) -> bool {
-        /*unsafe*/
-        { libc::WIFEXITED(self.0) }
+        libc::WIFEXITED(self.0)
     }
 
     pub fn success(&self) -> bool {
@@ -360,19 +359,11 @@ pub fn success(&self) -> bool {
     }
 
     pub fn code(&self) -> Option<i32> {
-        if self.exited() {
-            Some(/*unsafe*/ { libc::WEXITSTATUS(self.0) })
-        } else {
-            None
-        }
+        if self.exited() { Some(libc::WEXITSTATUS(self.0)) } else { None }
     }
 
     pub fn signal(&self) -> Option<i32> {
-        if !self.exited() {
-            Some(/*unsafe*/ { libc::WTERMSIG(self.0) })
-        } else {
-            None
-        }
+        if !self.exited() { Some(libc::WTERMSIG(self.0)) } else { None }
     }
 }
 

library/std/src/sys/vxworks/thread_local_dtor.rs

@@ -2,6 +2,6 @@
 #![unstable(feature = "thread_local_internals", issue = "none")]
 
 pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) {
-    use crate::sys_common::thread_local::register_dtor_fallback;
+    use crate::sys_common::thread_local_dtor::register_dtor_fallback;
     register_dtor_fallback(t, dtor);
 }

src/bootstrap/cc_detect.rs

@@ -132,7 +132,8 @@ pub fn find(build: &mut Build) {
             false
         };
 
-        if cxx_configured {
+        // for VxWorks, record CXX compiler which will be used in lib.rs:linker()
+        if cxx_configured || target.contains("vxworks") {
             let compiler = cfg.get_compiler();
             build.cxx.insert(target, compiler);
         }

src/bootstrap/lib.rs

@@ -857,6 +857,10 @@ fn linker(&self, target: TargetSelection, can_use_lld: bool) -> Option<&Path> {
         if let Some(linker) = self.config.target_config.get(&target).and_then(|c| c.linker.as_ref())
         {
             Some(linker)
+        } else if target.contains("vxworks") {
+            // need to use CXX compiler as linker to resolve the exception functions
+            // that are only existed in CXX libraries
+            Some(self.cxx[&target].path())
         } else if target != self.config.build
             && util::use_host_linker(target)
             && !target.contains("msvc")