https://bugs.gentoo.org/790176
https://github.com/ledger/ledger/issues/2030

From fa37f595b3c44dc7ac86b29d105ae6417c3e0080 Mon Sep 17 00:00:00 2001
From: Sam James <sam@gentoo.org>
Date: Mon, 14 Jun 2021 12:37:58 +0000
Subject: [PATCH] Fix compilation with Boost 1.76
--- a/src/expr.cc
+++ b/src/expr.cc
@@ -35,6 +35,8 @@
 #include "parser.h"
 #include "scope.h"
 
+#include <boost/smart_ptr/scoped_ptr.hpp>
+
 namespace ledger {
 
 expr_t::expr_t() : base_type()
--- a/src/format.h
+++ b/src/format.h
@@ -45,6 +45,8 @@
 #include "expr.h"
 #include "unistring.h"
 
+#include <boost/smart_ptr/scoped_ptr.hpp>
+
 namespace ledger {
 
 class unistring;