[mutter] Declare clutter version constants as extern

[Mario Sanchez Prada <msanchez src gnome org>]

commit 813de50eba98ff4bcf51cc5ecb389d72862f461a
Author: Mario Sanchez Prada <mario endlessm com>
Date:   Thu Apr 13 13:08:22 2017 +0100

    Declare clutter version constants as extern
    
    These constants got the CLUTTER_VAR annotations removed when making
    it a private library, so the extern modifier needs to be explicitly added.

 clutter/clutter/clutter-version.h.in |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/clutter/clutter/clutter-version.h.in b/clutter/clutter/clutter-version.h.in
index 29cf537..08ddd58 100644
--- a/clutter/clutter/clutter-version.h.in
+++ b/clutter/clutter/clutter-version.h.in
@@ -312,7 +312,7 @@ G_BEGIN_DECLS
  *
  * Since: 1.2
  */
-const guint clutter_major_version;
+extern const guint clutter_major_version;
 
 /**
  * clutter_minor_version:
@@ -326,7 +326,7 @@ const guint clutter_major_version;
  *
  * Since: 1.2
  */
-const guint clutter_minor_version;
+extern const guint clutter_minor_version;
 
 /**
  * clutter_micro_version:
@@ -340,7 +340,7 @@ const guint clutter_minor_version;
  *
  * Since: 1.2
  */
-const guint clutter_micro_version;
+extern const guint clutter_micro_version;
 
 G_END_DECLS