Welcome to LQ.
'lsocket' = libsocket.so or libsocket.a
... Which software are you compiling ? ?
Packages containing libsocket.* , examples :
camsource, libcamsource*, libferris-context_sockets, pfe-forth-devel, ctrlproxy.
http://rpm.pbone.net/ > Search > Advanced Search : libsocket.so
.