From 70c19e312ae86919bd77b39d45fa35dc4b66d458 Mon Sep 17 00:00:00 2001
From: Marcel Metz <mmetz@adrian-broher.net>
Date: Sun, 21 Aug 2016 20:23:48 +0200
Subject: [PATCH] Use old boost::optional implementation for boost 1.61

Fixes #777

- boost::spirit v 1.61 relies on the fact that the `Variant` template
  type of `boost::spirit::qi::detail::find_substitute` typedefs a
  `types` subtype.
- For the failing instantiation of `find_substition` a
  `boost::optional` is used as `Variant` template type.
- `boost::optional` removed its `types` subtype implementation with
  commit [boost::optional b5b8414c0], which means that this type is
  missing on every boost version 1.61 and onwards (until fixed of course).
- Using the BOOST_OPTIONAL_CONFIG_USE_OLD_IMPLEMENTATION_OF_OPTIONAL
  reenables the old implementation of boost::optional, which provides a
  `types` subtype.

This commits enables said define for boost 1.61 only, because I consider
this an upstream bug.  The upstream bug is tracked as [boost #12349].

[boost::optional b5b8414c0]: https://github.com/boostorg/optional/commit/b5b8414c069a2c5f16cc1f9813d069c8b36e2c35
[boost #12349]: https://svn.boost.org/trac/boost/ticket/12349
---
 CMakeLists.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3e70e72..65f1537 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -143,6 +143,16 @@ find_package(Boost ${MINIMUM_BOOST_VERSION} COMPONENTS chrono date_time filesyst
 find_package(ZLIB REQUIRED)
 find_package(Freetype REQUIRED)
 
+if(${Boost_VERSION} EQUAL "106100")
+    # with boost 1.61 some boost::optional internals were changed. However
+    # 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
+    add_definitions(
+        -DBOOST_OPTIONAL_CONFIG_USE_OLD_IMPLEMENTATION_OF_OPTIONAL
+    )
+endif()
+
 include_directories(
     ${Boost_INCLUDE_DIRS}
     ${ZLIB_INCLUDE_DIR}