[libglnx] macros: Fix casting for C++ compatibility

[Colin Walters <walters src gnome org>]

commit 900caea698690b18db4f2a9cd2c3abb4f84f10b5
Author: Colin Walters <walters verbum org>
Date:   Sun Dec 6 20:29:55 2020 +0000

    macros: Fix casting for C++ compatibility
    
    Prep for more work on porting rpm-ostree to use cxx-rs.

 glnx-macros.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/glnx-macros.h b/glnx-macros.h
index 7b3afd4..3177bb6 100644
--- a/glnx-macros.h
+++ b/glnx-macros.h
@@ -136,7 +136,7 @@ G_BEGIN_DECLS
          guard && ({ g_hash_table_iter_init (&it, ht), TRUE; });               \
          guard = FALSE)                                                        \
             for (kt k; guard; guard = FALSE)                                   \
-                for (vt v; g_hash_table_iter_next (&it, (gpointer)&k, (gpointer)&v);)
+                for (vt v; g_hash_table_iter_next (&it, (void**)&k, (void**)&v);)
 
 
 /* Cleaner method to iterate over a GHashTable. I.e. rather than