add pthread_getattr_np() and pthread_attr_getstack() support for illumos and Solaris systems

src/unix/solarish/mod.rs

@@ -2266,6 +2266,15 @@ extern "C" {
         f: extern "C" fn(*mut ::c_void) -> *mut ::c_void,
         value: *mut ::c_void,
     ) -> ::c_int;
+    pub fn pthread_getattr_np(
+        thread: ::pthread_t,
+        attr: *mut ::pthread_attr_t,
+    ) -> ::c_int;
+    pub fn pthread_attr_getstack(
+        attr: *const ::pthread_attr_t,
+        stackaddr: *mut *mut ::c_void,
+        stacksize: *mut ::size_t,
+    ) -> ::c_int;
     pub fn pthread_condattr_getclock(
         attr: *const pthread_condattr_t,
         clock_id: *mut clockid_t,