Convert the following uses:

contrib/ipfilter/netinet/fil.c:                 n = m_get(MB_DONTWAIT, m->m_type);
contrib/ipfilter/netinet/fil.c:                 n = m_get(M_DONTWAIT, m->m_type);
contrib/ipfilter/netinet/ip_fil.c:      m = m_get(M_DONTWAIT, MT_HEADER);
contrib/ipfilter/netinet/ip_fil.c:              m = m_get(M_DONTWAIT, MT_HEADER);
emulation/linux/linux_socket.c:         control = m_get(MB_WAIT, MT_CONTROL);
emulation/43bsd/43bsd_socket.c:         control = m_get(MB_WAIT, MT_CONTROL);

Sizes must be programatically determined for the first argument to m_getb, if it is non-obvious a comment should be added above the call to m_getb briefly explaining what is to be put into the mbuf.