Macros starting with `h' in BSD4-4

• HHALF libkern/quad.h:94
• HIADDR i386/isa/if_apx.c:317
• HOLDRELE sys/vnode.h:194
• howmany sys/param.h:175
• HTOC netiso/clnp.h:76
• htonl i386/include/endian.h:76
• htons i386/include/endian.h:77