htonll, ntohll on aarch64

[coypu%sdf.org@localhost]

aarch64 (-el) defines these two symbols
common/lib/libc/arch/aarch64/gen/byte_swap_8.S

#if BYTE_ORDER == LITTLE_ENDIAN
STRONG_ALIAS(_C_LABEL(ntohll), FUNC)
STRONG_ALIAS(_C_LABEL(htonll), FUNC)
#endif


it is the sole netbsd architecture to do so.

As such, there is no matching declaration in netbsd headers, so more
strict error-checking will show an implicit declaration.

(collectd does a link-check for htonll, and then tries to use it and
fails on it being an implicit declaration. I can force it not to find
htonll, though.)

Since we haven't had a netbsd release with aarch64 yet, it might be
worthwhile to just remove the symbols.

Thoughts?