"UINT64_C was not declared in this scope" issue on Code::Blocks fix

To fix the problem include the macro definition INT64_C(c) (c ## LL) and UINT64_C(c) (c ## ULL) before including the ffmgep library.

#include <iostream>

#ifndef INT64_C
#define INT64_C(c) (c ## LL)
#define UINT64_C(c) (c ## ULL)
#endif

extern "C"{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
}

int main(int argc, char *argv[])
{
   av_register_all();



    return 0;
}