FILE*-related calls usage statistics (after bff762ea01):

5 - fprintf - tr_sys_file_write_fmt (new)
4 - fopen   - tr_sys_file_open
4 - fclose  - tr_sys_file_close
2 - fflush  - tr_sys_file_flush
2 - fgets   - tr_sys_file_read_line (new)
2 - fputs   - tr_sys_file_write_line (new)
1 - fwrite  - tr_sys_file_write