Calls the System V IPC function msgrcv to receive a message from
message queue ID into variable VAR with a maximum message size of
SIZE. Note that when a message is received, the message type as a
native long integer will be the first thing in VAR, followed by the
actual message. This packing may be opened with
Taints the variable. Returns true if successful, false
on error. See also SysV IPC in perlipc and the documentation for
Portability issues: msgrcv in perlport.