[cogl/cogl.windows.fixes] cogl/cogl-debug.h: Export and properly use _cogl_debug_instances

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

commit f51c2480094dabbd15d4278fec8e21816174fedd
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Feb 13 17:36:22 2019 +0800

    cogl/cogl-debug.h: Export and properly use _cogl_debug_instances
    
    We need to also export the extern variables _cogl_debug_instances its
    consumption in Cogl-Path, so that it can be properly referred to by
    Cogl-Path and hence any other libraries that make use of them, such as
    Clutter.
    
    On Visual Studio DLL builds, this *must* also be marked with
    __declspec(dllimport) when Cogl-Path is being built against Cogl so that
    it can be referred to properly, otherwise one will be subject to crashes
    as a result.

 cogl/cogl-debug.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/cogl/cogl-debug.h b/cogl/cogl-debug.h
index 91a49e16..f59f3c87 100644
--- a/cogl/cogl-debug.h
+++ b/cogl/cogl-debug.h
@@ -79,12 +79,13 @@ typedef enum {
   COGL_DEBUG_N_FLAGS
 } CoglDebugFlags;
 
-extern GHashTable *_cogl_debug_instances;
+/* _cogl_debug_flags and _cogl_debug_instances currently needs to exported
+ * outside of the shared library for cogl-pango and cogl-path. The special
+ * COGL_EXPORT macro is needed to get this to work when building with MSVC.
+ */
+COGL_EXPORT extern GHashTable *_cogl_debug_instances;
 #define COGL_DEBUG_N_LONGS COGL_FLAGS_N_LONGS_FOR_SIZE (COGL_DEBUG_N_FLAGS)
 
-/* _cogl_debug_flags currently needs to exported outside of the shared
-   library for cogl-pango. The special COGL_EXPORT macro is needed to
-   get this to work when building with MSVC */
 COGL_EXPORT extern unsigned long _cogl_debug_flags[COGL_DEBUG_N_LONGS];
 
 #define COGL_DEBUG_ENABLED(flag) \