conflicting declaration for typedef when using C header in C++ application

There is a header file say header1.h from a C library. In header1.h,

  51 enum ConnectionState {
  52     InProgress = 0,
  53     BannerWaitEol = 1,
  54     BannerDone = 2,
  55     Finished = 3,
  56 };
  57 typedef uint8_t ConnectionState;

I use it in my C++ code as

extern "C"
{
#include "header1.h"
}

But I got a compile error

header1.h:57:17: error: conflicting declaration 'typedef uint8_t ConnectionState'
 typedef uint8_t ConnectionState;
                 ^~~~~~~~~~~~~~~~~~
header1.h:51:6: note: previous declaration as 'enum ConnectionState'
 enum ConnectionState {
      ^~~~~~~~~~~~~~~~~~

I read the post: Conflicting declaration in c++. And now I understand it is the typedef difference between C and C++. But I can not change header1.h because it is from a third-party library. How do I use this header1.h in my C++ application? Thank you for your help.