[gcr] gcr: Fix up the gcr-secret-exchange.h header

[Stefan Walter <stefw src gnome org>]

commit e4b4d14fbe700e813dbdaeb058985c1ebc9c3043
Author: Stef Walter <stefw collabora co uk>
Date:   Thu Oct 27 13:20:01 2011 +0200

    gcr: Fix up the gcr-secret-exchange.h header

 gcr/gcr-secret-exchange.h |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gcr/gcr-secret-exchange.h b/gcr/gcr-secret-exchange.h
index 28b45b9..aa95c0f 100644
--- a/gcr/gcr-secret-exchange.h
+++ b/gcr/gcr-secret-exchange.h
@@ -21,6 +21,10 @@
  * Author: Stef Walter <stefw collabora co uk>
  */
 
+#if !defined (__GCR_INSIDE_HEADER__) && !defined (GCR_COMPILATION)
+#error "Only <gcr/gcr.h> or <gcr/gcr-base.h> can be included directly."
+#endif
+
 #ifndef __GCR_SECRET_EXCHANGE_H__
 #define __GCR_SECRET_EXCHANGE_H__