Upstream: yes, will be in 0.4.8

From 9d55160487c658695cb86a57104e69833b287604 Mon Sep 17 00:00:00 2001
From: Jan Beich <jbeich@FreeBSD.org>
Date: Sat, 14 Jul 2018 13:33:24 +0000
Subject: [PATCH] Limit Spirit workaround for Boost < 1.67

---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5b2fe63a7..adde763a8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -262,7 +262,7 @@ set_property(DIRECTORY APPEND
         # boost::spirit relies on some API the old implementation provided.
         # This define enables the usage of the old boost::optional
         # implementation.  Boost upstream tracks this bug as #12349
-        $<$<VERSION_GREATER:${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION},1.60>:BOOST_OPTIONAL_CONFIG_USE_OLD_IMPLEMENTATION_OF_OPTIONAL>
+        $<$<AND:$<VERSION_GREATER:${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION},1.60>,$<VERSION_LESS:${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION},1.67>>:BOOST_OPTIONAL_CONFIG_USE_OLD_IMPLEMENTATION_OF_OPTIONAL>
 
         # We don't need localized output of Boost date_time and not setting
         # the define causes the inclusion of code, which contains std::tolower.
-- 
2.18.0