move out c/cpp/py

cl/_testrt/hello/libc/libc.go

@@ -0,0 +1,14 @@
+package libc
+
+import "C"
+import _ "unsafe"
+
+const (
+	LLGoPackage = "decl"
+)
+
+//go:linkname Printf C.printf
+func Printf(format *int8, __llgo_va_list ...any)
+
+//go:linkname Strlen C.strlen
+func Strlen(str *int8) C.int