feat: remove Singal in wasm freestanding

Author: hunjixin

src/os/file_other.go

@@ -42,6 +42,10 @@ func NewFile(fd uintptr, name string) *File {
 // Read reads up to len(b) bytes from machine.Serial.
 // It returns the number of bytes read and any error encountered.
 func (f stdioFileHandle) Read(b []byte) (n int, err error) {
+	if f != 0 {
+		return 0, ErrUnsupported
+	}
+
 	if len(b) == 0 {
 		return 0, nil
 	}

src/syscall/syscall_nonhosted.go

@@ -1,5 +1,5 @@
-//go:build baremetal || js || wasm_freestanding
-// +build baremetal js wasm_freestanding
+//go:build baremetal || js
+// +build baremetal js
 
 package syscall
 

src/syscall/tables_nonhosted.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build baremetal || nintendoswitch || js || wasm_freestanding
-// +build baremetal nintendoswitch js wasm_freestanding
+//go:build baremetal || nintendoswitch || js
+// +build baremetal nintendoswitch js
 
 package syscall
 

targets/wasm-freestanding.json

@@ -2,7 +2,7 @@
 	"llvm-target":   "wasm32-unknown-unknown",
 	"cpu":           "generic",
 	"features":      "+bulk-memory,+nontrapping-fptoint,+sign-ext",
-	"build-tags":    ["tinygo.wasm", "unknown_wasm", "runtime_memhash_leveldb"],
+	"build-tags":    ["tinygo.wasm", "wasm_freestanding", "runtime_memhash_leveldb"],
 	"goos":          "linux",
 	"goarch":        "arm",
 	"linker":        "wasm-ld",