[pan: 6/7] This works better. Either I can't program C++ or the compiler is being weird.

[Dominique Dumont <ddumont src gnome org>]

commit d1587a52f96b222f15d481e7c7a9c24788b4018f
Author: Thomas Tanner <thosrtanner googlemail com>
Date:   Sat Jun 25 20:38:22 2022 +0100

    This works better.
    Either I can't program C++ or the compiler is being weird.

 pan/general/article_number.h | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/pan/general/article_number.h b/pan/general/article_number.h
index e9cf1dc..7c3d908 100644
--- a/pan/general/article_number.h
+++ b/pan/general/article_number.h
@@ -22,6 +22,8 @@ class Article_Count
 
     explicit Article_Count(StringView const &);
 
+    Article_Count(Article_Count const &rhs) = default;
+
     explicit operator type () const { return val_; }
 
     Article_Count &operator=(Article_Count const &val)
@@ -119,6 +121,8 @@ class Article_Number {
     explicit Article_Number(type x) : val_(x) {}
     explicit Article_Number(StringView const &);
 
+    Article_Number(Article_Number const &rhs) = default;
+
     explicit operator type () const { return val_; }
 
     Article_Number &operator=(Article_Number const &val)