A while ago I posted a call for help (only to autoconf@) taking inventories of which C headers are provided by which OSes. It rapidly became clear that my methodology was far too crude, and I've spent much of the past six weeks coding up something much more sophisticated. The project is now at the point where I feel comfortable sharing it with a wider audience. Please see
http://hacks.owlfolio.org/header-survey/ for the results so far, and
https://github.com/zackw/header-survey/ for code, raw data, and instructions for contributing inventories for OSes not yet in the big table. (Big table only known to work properly in Firefox, say sorry - patches for the bad stylin' in Webkit most welcome. I've exhausted my ability to sling CSS.)
If you sent me an inventory already but your OS is not in the big table, I need you to send it again using the current `scansys.py`. To those of you who told me that it didn't work with your version of Python, take heart - it is now tested to work with 2.0. Yes, 2.0.