[glibmm/private-export-2-64] glib/glibmm/private/*.h: Decorate the classes with GLIBMM_API

[Chun-wei Fan <fanchunwei src gnome org>]

commit 3817d080993246a399649d3561a3cbbc03dae1d2
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Fri Aug 28 15:48:03 2020 +0800

    glib/glibmm/private/*.h: Decorate the classes with GLIBMM_API
    
    This is done for completeness' sake, as we are doing for the private headers that we
    generate.

 glib/glibmm/private/interface_p.h | 2 +-
 glib/glibmm/private/object_p.h    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/glib/glibmm/private/interface_p.h b/glib/glibmm/private/interface_p.h
index a116e0e3..6e1e54a2 100644
--- a/glib/glibmm/private/interface_p.h
+++ b/glib/glibmm/private/interface_p.h
@@ -8,7 +8,7 @@
 namespace Glib
 {
 
-class Interface_Class : public Glib::Class
+class GLIBMM_API Interface_Class : public Glib::Class
 {
 public:
   using CppObjectType = Interface;
diff --git a/glib/glibmm/private/object_p.h b/glib/glibmm/private/object_p.h
index 98ee09b6..9151f67b 100644
--- a/glib/glibmm/private/object_p.h
+++ b/glib/glibmm/private/object_p.h
@@ -8,7 +8,7 @@
 namespace Glib
 {
 
-class Object_Class : public Glib::Class
+class GLIBMM_API Object_Class : public Glib::Class
 {
 public:
   using CppObjectType = Object;