Attempting to fix b=288626, this will probably require setting MOZILLA_INTERNAL_API define in the xcode project, as I mentioned in the bug.

camino/PreferencePanes/Shared/PreferencePaneBase.mm

@@ -38,6 +38,7 @@
 
 #import "PreferencePaneBase.h"
 
+#include "nsCOMPtr.h"
 #include "nsIServiceManager.h"
 #include "nsIPref.h"