Some systems do not have these types available, and they are simply
convenience aliases. Instead use the expanded versions which are more
portable.
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=101192
This maps more closely the location of the real header. For
transitional purposes keep a <bsd/ip_icmp.h> that warns and includes
<bsd/netinet/ip_icmp.h>.