Problem:
When mysqlbinlog tries to read a big record (over 128KB) from stdin,
the glibc read in my_read will return 128KB instead of the full size.
This causes _my_b_read to fail which in turn results in a mysqlbinlog error.

Fix:
In mysqlbinlog set the flag MY_FULL_IO when reading from stdin,
so that my_read processes the complete chunk of data which is until EOF is found.