libavutil/log.c:106: error: Integer Overflow L1
  (0 - 1):unsigned64.

libavutil/log.c:82:1: <LHS trace>
80. }
81. 
82. void av_log_default_callback(void* ptr, int level, const char* fmt, va_list vl)
    ^
83. {
84.     static int print_prefix=1;

libavutil/log.c:82:1: Array declaration
80. }
81. 
82. void av_log_default_callback(void* ptr, int level, const char* fmt, va_list vl)
    ^
83. {
84.     static int print_prefix=1;

libavutil/log.c:106:19: Binary operation: (0 - 1):unsigned64
104.     vsnprintf(line + strlen(line), sizeof(line) - strlen(line), fmt, vl);
105. 
106.     print_prefix= line[strlen(line)-1] == '\n';
                       ^
107. 
108. #if HAVE_ISATTY
