[PUSHED] Building with --disable-database-connectivity

[Tor Lillqvist]

Hmm, I am not sure. I still think it might be too early to start
trying to use --disable-database-connectivity for "normal" OSes. (Even
if building for "headless"). But what the heck, pushed it anyway, with
a slight modification: instead of introducing conditionals in
Library_sc.mk to bypass just one source file, I bypass its contents
with #ifndef DISABLE_DBCONNECTIVITY.

--tml