external/boost: Silence Boost bind deprecation warning

> In file included from desktop/source/lib/lokinteractionhandler.cxx:22:
> In file included from external/boost/include/boost/property_tree/json_parser.hpp:30:
> In file included from workdir/UnpackedTarball/boost/boost/property_tree/json_parser.hpp:16:
> In file included from workdir/UnpackedTarball/boost/boost/property_tree/json_parser/detail/read.hpp:13:
> In file included from workdir/UnpackedTarball/boost/boost/property_tree/json_parser/detail/parser.hpp:7:
> In file included from external/boost/include/boost/bind.hpp:30:
> workdir/UnpackedTarball/boost/boost/bind.hpp:36:1: warning: The practice of declaring the Bind placeholders (_1, _2, ...) in the global namespace is deprecated. Please use <boost/bind/bind.hpp> + using namespace boost::placeholders, or define BOOST_BIND_GLOBAL_PLACEHOLDERS to retain the current behavior. [-W#pragma-messages]
> BOOST_PRAGMA_MESSAGE(
> ^

etc. from within boost/property_tree/json_parser.hpp wherever that is included,
since e0f1b5bd94550835c639efda4e4c9a801c78dbe9 "Upgrade external/boost to latest
Boost 1.75.0".

Change-Id: I2c780966e4774a8d58d1cbdf21f77d685da00689
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/109229
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

2 files changed, 51 insertions, 0 deletions

diff --git a/external/boost/0001-Fix-usage-of-deprecated-Boost.Bind-features.patch.2 b/external/boost/0001-Fix-usage-of-deprecated-Boost.Bind-features.patch.2
new file mode 100644
index 000000000000..583a9d905214
--- /dev/null
+++ b/external/boost/0001-Fix-usage-of-deprecated-Boost.Bind-features.patch.2
@@ -0,0 +1,48 @@
+From d1c8825a45a0717e1ad79583d3283b0e5e32831e Mon Sep 17 00:00:00 2001
+From: Andrey Semashev <Lastique@users.noreply.github.com>
+Date: Tue, 28 Apr 2020 22:03:04 +0300
+Subject: [PATCH] Fix usage of deprecated Boost.Bind features
+
+This fixes deprecation warnings generated by boost/bind.hpp.
+
+Also, use a more actual include path for ref.hpp.
+---
+ include/boost/property_tree/json_parser/detail/parser.hpp | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/include/boost/property_tree/json_parser/detail/parser.hpp b/include/boost/property_tree/json_parser/detail/parser.hpp
+index 5554990..6cf6363 100644
+--- a/include/boost/property_tree/json_parser/detail/parser.hpp
++++ b/include/boost/property_tree/json_parser/detail/parser.hpp
+@@ -3,8 +3,8 @@
+ 
+ #include <boost/property_tree/json_parser/error.hpp>
+ 
+-#include <boost/ref.hpp>
+-#include <boost/bind.hpp>
++#include <boost/core/ref.hpp>
++#include <boost/bind/bind.hpp>
+ #include <boost/format.hpp>
+ 
+ #include <iterator>
+@@ -214,7 +214,7 @@ namespace boost { namespace property_tree {
+         void process_codepoint(Sentinel end, EncodingErrorFn error_fn) {
+             encoding.transcode_codepoint(cur, end,
+                 boost::bind(&Callbacks::on_code_unit,
+-                            boost::ref(callbacks), _1),
++                            boost::ref(callbacks), boost::placeholders::_1),
+                 error_fn);
+         }
+ 
+@@ -517,7 +517,7 @@ namespace boost { namespace property_tree {
+         void feed(unsigned codepoint) {
+             encoding.feed_codepoint(codepoint,
+                                     boost::bind(&Callbacks::on_code_unit,
+-                                                boost::ref(callbacks), _1));
++                                                boost::ref(callbacks), boost::placeholders::_1));
+         }
+ 
+         Callbacks& callbacks;
+-- 
+2.29.2
+
diff --git a/external/boost/UnpackedTarball_boost.mk b/external/boost/UnpackedTarball_boost.mk
index db956c916df5..bdacdcd9856e 100644
--- a/external/boost/UnpackedTarball_boost.mk
+++ b/external/boost/UnpackedTarball_boost.mk
@@ -35,6 +35,9 @@ boost_patches += windows-no-utf8-locales.patch.0
 
 boost_patches += msvc2017.patch.0
 
+# Included in boost-1.76.0:
+boost_patches += 0001-Fix-usage-of-deprecated-Boost.Bind-features.patch.2
+
 $(eval $(call gb_UnpackedTarball_UnpackedTarball,boost))
 
 $(eval $(call gb_UnpackedTarball_set_tarball,boost,$(BOOST_TARBALL)))