compositor-wayland: Convert sprawl flag to boolean

Signed-off-by: Armin Krezović <krezovic.armin@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
diff --git a/libweston/compositor-wayland.h b/libweston/compositor-wayland.h
index 9a9dde8..3ca875a 100644
--- a/libweston/compositor-wayland.h
+++ b/libweston/compositor-wayland.h
@@ -39,7 +39,7 @@
 struct weston_wayland_backend_config {
 	struct weston_backend_config base;
 	bool use_pixman;
-	int sprawl;
+	bool sprawl;
 	char *display_name;
 	int fullscreen;
 	char *cursor_theme;