>I have tried a few other combinations but gcc always comes back with unknow
>file extension for the libsocket.sl share library?

>gcc test.o /usr/lib/libdce.a /usr/lib/cxl.a /usr/lib/libsocket.sl -o test

Try it thusly:

gcc test.o -ldce -lc --for-linker="-WL,XL=/usr/lib/libsocket.sl" -o test

Normal .a are specified with the conventional -l<lib>. Specifying which
shared libraries to use needs to get passed through to LINKEDIT and is
done as above.