ipcpipeline: cleanup header includes

We are only using read(), write(), memcpy(), strlen() and errno
in ipcpipelinecomm.c. Everything else is glib/gstreamer.

sys/ipcpipeline/gstipcpipelinecomm.c

@@ -27,7 +27,6 @@
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
-#include <stdlib.h>
 #include <gst/base/gstbytewriter.h>
 #include <gst/gstprotection.h>
 #include "gstipcpipelinecomm.h"

sys/ipcpipeline/gstipcpipelinecomm.h

@@ -24,7 +24,6 @@
 #ifndef __GST_IPC_PIPELINE_COMM_H__
 #define __GST_IPC_PIPELINE_COMM_H__
 
-#include <glib.h>
 #include <gst/gst.h>
 #include <gst/base/gstadapter.h>
 

sys/ipcpipeline/gstipcpipelinesink.c

@@ -73,9 +73,7 @@
 #  include "config.h"
 #endif
 
-#include <unistd.h>
 #include "gstipcpipelinesink.h"
-#include <string.h>
 
 static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,

sys/ipcpipeline/gstipcpipelinesrc.c

@@ -40,10 +40,6 @@
 #  include "config.h"
 #endif
 
-#include <unistd.h>
-#include <stdlib.h>
-#include <string.h>
-
 #include "gstipcpipelinesrc.h"
 
 static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",