gtsam: backport a patch for C++17 compatibility

recipes/gtsam/all/conandata.yml

@@ -45,6 +45,9 @@ patches:
     - patch_file: "patches/4.0.2-0003-macos-rpath.patch"
       patch_description: "Relocatable shared libs on Apple OS"
       patch_type: "conan"
-    - patch_file: "patches/4.0.2-0003-cmake-project.patch"
+    - patch_file: "patches/4.0.2-0004-cmake-project.patch"
       patch_description: "CMake: move project() after cmake_minimum_required()"
       patch_type: "conan"
+    - patch_file: "patches/4.0.2-0005-replace-ptr_fun.patch"
+      patch_description: "Replace deprecated `ptr_fun` with lambda expression for C++17"
+      patch_type: "portability"

recipes/gtsam/all/patches/4.0.2-0005-replace-ptr_fun.patch

@@ -0,0 +1,55 @@
+From 4a1491876d5a96ea791c0e17204ace05f6eb206a Mon Sep 17 00:00:00 2001
+From: Frank Dellaert <dellaert@gmail.com>
+Date: Sat, 12 Oct 2019 14:14:10 -0400
+Subject: [PATCH] Replace deprecated `ptr_fun` with lambda expression
+
+---
+ gtsam/linear/GaussianBayesNet.cpp  | 12 ++++++------
+ gtsam/linear/GaussianBayesTree.cpp |  4 ++--
+ 2 files changed, 8 insertions(+), 8 deletions(-)
+
+diff --git a/gtsam/linear/GaussianBayesNet.cpp b/gtsam/linear/GaussianBayesNet.cpp
+index bc96452b92..e9938ceb65 100644
+--- a/gtsam/linear/GaussianBayesNet.cpp
++++ b/gtsam/linear/GaussianBayesNet.cpp
+@@ -187,16 +187,16 @@ namespace gtsam {
+   }
+
+   /* ************************************************************************* */
+-  double GaussianBayesNet::logDeterminant() const
+-  {
++  double GaussianBayesNet::logDeterminant() const {
+     double logDet = 0.0;
+-    for(const sharedConditional& cg: *this) {
+-      if(cg->get_model()) {
++    for (const sharedConditional& cg : *this) {
++      if (cg->get_model()) {
+         Vector diag = cg->R().diagonal();
+         cg->get_model()->whitenInPlace(diag);
+-        logDet += diag.unaryExpr(ptr_fun<double,double>(log)).sum();
++        logDet += diag.unaryExpr([](double x) { return log(x); }).sum();
+       } else {
+-        logDet += cg->R().diagonal().unaryExpr(ptr_fun<double,double>(log)).sum();
++        logDet +=
++            cg->R().diagonal().unaryExpr([](double x) { return log(x); }).sum();
+       }
+     }
+     return logDet;
+diff --git a/gtsam/linear/GaussianBayesTree.cpp b/gtsam/linear/GaussianBayesTree.cpp
+index 8d0fafb618..13c19bce65 100644
+--- a/gtsam/linear/GaussianBayesTree.cpp
++++ b/gtsam/linear/GaussianBayesTree.cpp
+@@ -40,11 +40,11 @@ namespace gtsam {
+     parentSum += clique->conditional()
+                      ->R()
+                      .diagonal()
+-                     .unaryExpr(std::ptr_fun<double, double>(log))
++                     .unaryExpr([](double x) { return log(x); })
+                      .sum();
+     return 0;
+   }
+-  }
++  }  // namespace internal
+
+   /* ************************************************************************* */
+   bool GaussianBayesTree::equals(const This& other, double tol) const