compile with Sun C, as "interface.h" isn't being included before the
structures are being declared.
Furthermore, in the files that Sun C *can* compile, it doesn't cause Sun
C to generate code that's safe with unaligned accesses, as
"__attribute__" is defined as a do-nothing macro with compilers that
don't support it.
Therefore, we get rid of that tag on the structures to which it was
added, and instead use "EXTRACT_16BIT()" and "EXTRACT_32BIT()" to fetch
16-bit and 32-bit big-endian quantities from packets. We also fix some
other references to multi-byte quantities to get rid of code that tries
to do unaligned loads on platforms that don't support them.
We also throw in a hack that makes those macros use
"__attribute__((packed))" on structures containing only one 16-bit or
32-bit integer to get the compiler to generate unaligned-safe code
rather than doing it by hand. (GCC on SPARC produces the same code that
doing it by hand does; I don't know if GCC on any other big-endian
strict-alignment processor generates better code for that case. On
little-endian processors, as "ntohs()" and "ntohl()" might be functions,
that might actually produce worse code.)
Fix some places to use "%u" rather than "%d" to print unsigned
quantities.
