wayland: Be consistent about #include-guard names

We had a mix of inconsistent names, some of which were non-conformant.
Standardize on all-uppercase-and-underscore naming convention.

https://bugs.freedesktop.org/show_bug.cgi?id=70679

cursor/xcursor.h

@@ -20,8 +20,8 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-#ifndef _XCURSOR_H_
-#define _XCURSOR_H_
+#ifndef XCURSOR_H
+#define XCURSOR_H
 
 typedef int		XcursorBool;
 typedef unsigned int	XcursorUInt;

src/wayland-client.h

@@ -20,8 +20,8 @@
  * OF THIS SOFTWARE.
  */
 
-#ifndef _WAYLAND_CLIENT_H
-#define _WAYLAND_CLIENT_H
+#ifndef WAYLAND_CLIENT_H
+#define WAYLAND_CLIENT_H
 
 #include "wayland-util.h"
 #include "wayland-version.h"

src/wayland-egl.h

@@ -21,8 +21,8 @@
  * OF THIS SOFTWARE.
  */
 
-#ifndef _WAYLAND_EGL_H
-#define _WAYLAND_EGL_H
+#ifndef WAYLAND_EGL_H
+#define WAYLAND_EGL_H
 
 #ifdef  __cplusplus
 extern "C" {

src/wayland-server.h

@@ -20,8 +20,8 @@
  * OF THIS SOFTWARE.
  */
 
-#ifndef WAYLAND_H
-#define WAYLAND_H
+#ifndef WAYLAND_SERVER_H
+#define WAYLAND_SERVER_H
 
 #ifdef  __cplusplus
 extern "C" {