More hacking

Add beginnings of Xv plugin
Add Poll event
Clean up props handling
V4l2 add beginnings of poll event

spa/plugins/xv/xv-utils.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sched.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <poll.h>
+
+#define CLEAR(x) memset(&(x), 0, sizeof(x))
+
+static int
+spa_xv_open (SpaXvSink *this)
+{
+  SpaXvState *state = &this->state;
+
+  if (state->opened)
+    return 0;
+
+  state->opened = true;
+
+  return 0;
+}
+
+static int
+spa_xv_set_format (SpaXvSink *this, SpaFormat *format, bool try_only)
+{
+  if (spa_xv_open (this) < 0)
+    return -1;
+
+  return 0;
+}
+
+static int
+spa_xv_close (SpaXvSink *this)
+{
+  SpaXvState *state = &this->state;
+
+  if (!state->opened)
+    return 0;
+
+  state->opened = false;
+
+  return 0;
+}
+
+static int
+spa_xv_start (SpaXvSink *this)
+{
+  if (spa_xv_open (this) < 0)
+    return -1;
+
+  return 0;
+}
+
+static int
+spa_xv_stop (SpaXvSink *this)
+{
+  spa_xv_close (this);
+
+  return 0;
+}