os: implement Getwd

src/syscall/file_emulated.go

@@ -0,0 +1,10 @@
+// +build baremetal wasi wasm
+
+// This file emulates some file-related functions that are only available
+// under a real operating system.
+
+package syscall
+
+func Getwd() (string, error) {
+	return "", nil
+}