refactor: add WF prefix for c/c++ binding members

wfassoc-cdylib/src/cstr_ffi.rs

@@ -9,11 +9,9 @@
 //! The only thing that outer programs should note is that this string is volatile,
 //! once they get it, they must dupliate it immediately before any futher calling to this dynamic library.
 use std::cell::RefCell;
-use std::ffi::{CStr, CString, c_char};
+use std::ffi::{CStr, CString};
 use thiserror::Error as TeError;
-
-/// The type representing the raw pointer to immutable C-style NUL-terminated string.
-pub type CStyleString = *const c_char;
+use crate::ffi_types::CStyleString;
 
 // region: Error