Alright, here's where I'm at.

First issue was it complaining about le16toh, le32toh, being undefined. Turned out they had included their own header with the relevant functions defined for compatibility for Android - so with that out of the way it at least builds (whether or not it will run correctly, now that I'm not so sure about, but one can hope. If not, I can painstakingly copy in the relevant pieces of endian.h and dependencies from a more recent glibc/eglibc out of the Debian armel libc6-dev package, and hope that will work). So I think that's a resolved-enough problem.

Second issue, and I'd like someone who knows more about this to chime in. These are undefined:
NL80211_CHAN_NO_HT
NL80211_ATTR_WIPHY_FREQ
NL80211_ATTR_WIPHY_CHANNEL_TYPE
..normally they ought to be defined in linux/nl80211, and I'm not quite sure if I'm just being dumb and not including the right package for build-depends, or if our 2.6.whatever kernel is too old to even have those. I know some NL80211 stuff is new in the 3.* line of Linux kernels, just not sure if all of it, or the parts we need, are.

If there's no headway on this for a while, I'm going to instead try to build the 1.2-rc1 version instead of the latest trunk revision, and if that's successful, I'll try to just package the newer airmon-ng (formerly airmon-zc) script in place of the less portable, not-busybox-ps-handing variant still in 1.2-rc1.