move out c/cpp/py

cl/_testrt/cstr/in.go

@@ -0,0 +1,13 @@
+package main
+
+import _ "unsafe"
+
+//go:linkname cstr llgo.cstr
+func cstr(string) *int8
+
+//go:linkname printf C.printf
+func printf(format *int8, __llgo_va_list ...any)
+
+func main() {
+	printf(cstr("Hello, world\n"))
+}