ipcpipeline: Rework compiler checks
pipe()
isn't used since 15927b65,
and socketpair()
from #include <sys/socket.h>
is used only in the
examples. In practice, you can use probably also use anything that
allows you to create fd pairs, such as named pipes or anonymous pipes.
We use the cross-platform GstPollFD API in the plugin.
+
some misc build fixes
Edited by Nirbheek Chauhan