Check for clang to enable correct discovery of supported warnings
Add new extras: url_q, url_n and url_c

Document the older urls using info on web site
Use smaller fixed buffer sizes on stack
Support staticflickr.com domain

http://www.flickr.com/services/api/misc.urls.html
http://www.flickr.com/services/api/misc.buddyicons.html

(flickcurl_photo_as_source_uri, flickcurl_user_icon_uri): Use new
domain for building image URIs.

(flickcurl_source_uri_as_photo_id): Accept old static.flickr.com as
well as new domain in URIs.
#changes