[gtksourceview] version: add a warning about the MIN_REQUIRED macro

[Sébastien Wilmet <swilmet src gnome org>]

commit 93c9cc75842ce53c7b3e9a57bc828e01d7865bf0
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sat Dec 19 21:19:49 2015 +0100

    version: add a warning about the MIN_REQUIRED macro

 gtksourceview/gtksourceversion.h.in |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)
---
diff --git a/gtksourceview/gtksourceversion.h.in b/gtksourceview/gtksourceversion.h.in
index 7026ef4..c7647a9 100644
--- a/gtksourceview/gtksourceversion.h.in
+++ b/gtksourceview/gtksourceversion.h.in
@@ -220,8 +220,13 @@ G_BEGIN_DECLS
  * This macro defines the lower bound for the GtkSourceView API to use.
  *
  * If a function has been deprecated in a newer version of GtkSourceView,
- * it is possible to use this symbol to avoid the compiler warnings
- * without disabling warning for every deprecated function.
+ * defining this symbol hides the compiler warnings for those functions
+ * without disabling warnings for the other deprecated functions.
+ *
+ * <warning>
+ * Warning: if you define this macro, do not forget to update it! Especially
+ * when writing new code. Otherwise you can miss the new deprecations.
+ * </warning>
  *
  * Since: 3.20
  */