Restored an explicit refill of the buffer in m_getfld() that I removed in the big stdio cleanup.  Its need is shown by reducing the message buffer size to 2048.
Restored an explicit refill of the buffer in m_getfld() that I
removed in the big stdio cleanup.  Its need is shown by reducing
the message buffer size to 2048.

dscho/nmh,dscho/nmh,dscho/nmh,mcr/nmh,mcr/nmh,dscho/nmh