[libhandy/unstable-api: 33/33] Forbid using HANDY_USE_UNSTABLE_API

[Adrien Plazas <aplazas src gnome org>]

commit 96601f6a7f854b0ee04b648fa203a479c2e194ce
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Wed Jul 29 14:04:53 2020 +0200

    Forbid using HANDY_USE_UNSTABLE_API
    
    To help applications know they should stop using HANDY_USE_UNSTABLE_API,
    error out if it is defined.

 src/handy.h | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/handy.h b/src/handy.h
index 3e025a6b..fe2d08ec 100644
--- a/src/handy.h
+++ b/src/handy.h
@@ -20,6 +20,10 @@ G_BEGIN_DECLS
 
 #define _HANDY_INSIDE
 
+#ifdef HANDY_USE_UNSTABLE_API
+#error    libhandy offers a stable API. You must stop defining HANDY_USE_UNSTABLE_API.
+#endif
+
 #include "hdy-version.h"
 #include "hdy-action-row.h"
 #include "hdy-animation.h"