I read some code...
I'm pretty sure the the problem is related to curl. The undefined references refer (sorry...) to definitions in cl_http.h; this one is included in client.h only if HAVE_CURL is defined (for the C preprocessor). The default behavior of configure script it to check whether curl is present or not; looking into config.h I can read
#define HAVE_CURL 1
so there shouldn't be any problem. But...
I have only one suspect, now... Well, actually a feeling, because I'm not an expert programmer. In client.h there is a line:
#define CURL_STATICLIB
Maybe the linker is looking for static libs, when I have only their dynamic version?
In my box I have these packages:
libcurl3 (7.17.0-1)
libcurl3-gnutls (7.17.0-1)
libcurl4-openssl (7.16.2-4)
libcurl4-openssl-dev (7.16.2-4)
The last one is the only (of course) providing curl.h