include: Switch to #pragma once pattern

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/vty/buffer.h b/include/osmocom/vty/buffer.h
index c9467a9..482a919 100644
--- a/include/osmocom/vty/buffer.h
+++ b/include/osmocom/vty/buffer.h
@@ -20,8 +20,7 @@
  * Boston, MA 02111-1307, USA.
  */
 
-#ifndef _ZEBRA_BUFFER_H
-#define _ZEBRA_BUFFER_H
+#pragma once
 
 #include <sys/types.h>
 
@@ -98,5 +97,3 @@
 */
 extern buffer_status_t buffer_flush_window(struct buffer *, int fd, int width,
 					   int height, int erase, int no_more);
-
-#endif				/* _ZEBRA_BUFFER_H */