Update WASIp3 WITs to 0.3.0

CMakeLists.txt

@@ -145,7 +145,7 @@ else()
 endif()
 
 set(wasip2-version 0.2.0)
-set(wasip3-version 0.3.0-rc-2026-03-15)
+set(wasip3-version 0.3.0)
 
 include(bindings)
 include(builtins)

expected/wasm32-wasip3/defined-symbols.txt

@@ -559,6 +559,7 @@ erfl
 errno
 exit
 exit_exit
+exit_exit_with_code
 exit_result_void_void_free
 exp
 exp10

expected/wasm32-wasip3/undefined-symbols.txt

@@ -54,6 +54,7 @@ __wasm_import_environment_get_arguments
 __wasm_import_environment_get_environment
 __wasm_import_environment_get_initial_cwd
 __wasm_import_exit_exit
+__wasm_import_exit_exit_with_code
 __wasm_import_filesystem_descriptor_drop
 __wasm_import_filesystem_method_descriptor_advise
 __wasm_import_filesystem_method_descriptor_append_via_stream

libc-bottom-half/cloudlibc/src/libc/poll/poll.c

@@ -493,6 +493,7 @@ static int poll_impl(struct pollfd *fds, size_t nfds, int timeout) {
 
 out:
   if (timeout_subtask != 0) {
+    wasip3_waitable_join(timeout_subtask, 0);
     wasip3_subtask_cancel(timeout_subtask);
     wasip3_subtask_drop(timeout_subtask);
   }

libc-bottom-half/cloudlibc/src/libc/stdlib/_Exit.c

@@ -10,7 +10,12 @@
 noreturn void _Exit(int status) {
 #if defined(__wasip1__)
   __wasi_proc_exit(status);
-#elif defined(__wasip2__) || defined(__wasip3__)
+#elif defined(__wasip2__)
+  exit_result_void_void_t exit_status = { .is_err = status != 0 };
+  exit_exit(&exit_status);
+#elif defined(__wasip3__)
+  if (status >= 0 && status <= 255)
+    exit_exit_with_code(status);
   exit_result_void_void_t exit_status = { .is_err = status != 0 };
   exit_exit(&exit_status);
 #else

libc-bottom-half/crt/crt1-command.c

@@ -18,8 +18,7 @@ __attribute__((export_name("_start"))) void _start(void)
 // that this shouldn't be too problematic (in theory).
 __attribute__((export_name("wasi:cli/run@0.2.0#run"))) int _start(void)
 #elif defined(__wasip3__)
-__attribute__((export_name("wasi:cli/run@0.3.0-rc-2026-03-15#run"))) int
-_start(void)
+__attribute__((export_name("wasi:cli/run@0.3.0#run"))) int _start(void)
 #else
 #error "Unsupported WASI version"
 #endif