MQEPH_* (Embedded command format header structure)

See:

MQEPH_STRUC_ID "EPHb"
MQEPH_STRUC_ID_ARRAY 'E','P','H','b'
MQEPH_STRUC_LENGTH_FIXED 68 X'00000044'
MQEPH_VERSION_1 1 X'00000001'
MQEPH_CURRENT_VERSION 1 X'00000001'