* plugin.cpp (includes): New.
(build_type): New function. To build a type named
__CtraceStruct__ holding stack space.
(build_function_decl): New function. To build a function declaration
with type void (*)(struct __CtraceStruct__ *, const char *).
(make_fname_decl): New Function. To build a var initialing with current
function name. Just like C's __FUNCTION__.
(execute_trace): Make use of all new function. Nearly finish but left
TODO.