sdk: make C++11 plugins build again
compositor.h must not define a 'static_assert' macro, since that
conflicts with the new 'static_assert' in the standard and breaks
the build.
diff --git a/desktop-shell/shell.c b/desktop-shell/shell.c
index 5f6bd6d..9fbac00 100644
--- a/desktop-shell/shell.c
+++ b/desktop-shell/shell.c
@@ -43,6 +43,10 @@
#define DEFAULT_NUM_WORKSPACES 1
#define DEFAULT_WORKSPACE_CHANGE_ANIMATION_LENGTH 200
+#ifndef static_assert
+#define static_assert(cond, msg)
+#endif
+
struct focus_state {
struct weston_seat *seat;
struct workspace *ws;