From a17c0d628d70b8aa0a6d81760770f72808740e2c Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Wed, 24 Jul 2019 10:35:36 +0200
Subject: [PATCH] Fix our usage of TBB and <thread.h>

A lot of parts of CGAL use `<thread>` in conjunction with TBB. I have
added the `find_package(Threads)` in `CGAL_target_use_TBB.cmake` for
convenience.

I have also restored FindTBB.cmake as a pure copy of
  https://github.com/Kitware/VTK/blob/master/CMake/FindTBB.cmake
with that version:

> c7249fed2e73ce25fbbc53363d9caf4ab5cc9195
> Author: Cory Quammen <cory.quammen@kitware.com>
> Date:   Thu Feb 14 23:21:09 2019 -0500
>
>     FindTBB: handle basic linker scripts
>
>     TBB binaries may define libtbb.so as a linker script of the form
>
>     INPUT(libtbb.so.2)
>
>     Make FindTBB find the real .so file libtbb.so points to in such cases.
>
>     Approach borrowed from vtk-m/CMake/VTKmDeviceAdapters.cmake on
>     suggestion from Robert Maynard.
>
>
---
 Installation/cmake/modules/CGAL_Common.cmake         | 3 ++-
 Installation/cmake/modules/CGAL_target_use_TBB.cmake | 6 ++++--
 Installation/cmake/modules/FindTBB.cmake             | 3 ---
 Installation/lib/cmake/CGAL/CGALConfig.cmake         | 2 ++
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/Installation/cmake/modules/CGAL_Common.cmake b/Installation/cmake/modules/CGAL_Common.cmake
index 9ade617f663..59f8190136d 100644
--- a/Installation/cmake/modules/CGAL_Common.cmake
+++ b/Installation/cmake/modules/CGAL_Common.cmake
@@ -61,5 +61,6 @@ if( NOT CGAL_COMMON_FILE_INCLUDED )
   # set use-file for Eigen3 (needed to have default solvers)
   set(EIGEN3_USE_FILE "UseEigen3")
 
-
+  set(TBB_USE_FILE "UseTBB")
+  include(${CMAKE_CURRENT_LIST_DIR}/CGAL_target_use_TBB.cmake)
 endif()
diff --git a/Installation/cmake/modules/CGAL_target_use_TBB.cmake b/Installation/cmake/modules/CGAL_target_use_TBB.cmake
index 23e9acd72f1..631ece6a286 100644
--- a/Installation/cmake/modules/CGAL_target_use_TBB.cmake
+++ b/Installation/cmake/modules/CGAL_target_use_TBB.cmake
@@ -4,7 +4,9 @@ endif()
 set(CGAL_target_use_TBB_included TRUE)
 
 function(CGAL_target_use_TBB target)
-  target_include_directories ( ${target} SYSTEM PUBLIC ${TBB_INCLUDE_DIRS} )
-  target_link_libraries( ${target} PUBLIC ${TBB_LIBRARIES} )
+  if(NOT TARGET Threads::Threads)
+    find_package(Threads REQUIRED)
+  endif()
+  target_link_libraries( ${target} PUBLIC TBB::tbb TBB::tbbmalloc Threads::Threads)
   target_compile_options( ${target} PUBLIC -DNOMINMAX -DCGAL_LINKED_WITH_TBB )
 endfunction()
diff --git a/Installation/cmake/modules/FindTBB.cmake b/Installation/cmake/modules/FindTBB.cmake
index 5e7dc208df8..b1a3d884c65 100644
--- a/Installation/cmake/modules/FindTBB.cmake
+++ b/Installation/cmake/modules/FindTBB.cmake
@@ -419,6 +419,3 @@ if(NOT TBB_VERSION)
         TBB_COMPATIBLE_INTERFACE_VERSION "${TBB_VERSION_CONTENTS}")
 
 endif()
-
-set(TBB_USE_FILE "UseTBB")
-include(${CMAKE_CURRENT_LIST_DIR}/CGAL_target_use_TBB.cmake)
diff --git a/Installation/lib/cmake/CGAL/CGALConfig.cmake b/Installation/lib/cmake/CGAL/CGALConfig.cmake
index c2b0aed549d..630117e24ad 100644
--- a/Installation/lib/cmake/CGAL/CGALConfig.cmake
+++ b/Installation/lib/cmake/CGAL/CGALConfig.cmake
@@ -140,6 +140,8 @@ include(${CGAL_MODULES_DIR}/CGAL_TweakFindBoost.cmake)
 cgal_setup_module_path()
 
 set(CGAL_USE_FILE ${CGAL_MODULES_DIR}/UseCGAL.cmake)
+set(TBB_USE_FILE "UseTBB")
+include(${CMAKE_CURRENT_LIST_DIR}/CGAL_target_use_TBB.cmake)
 
 include("${CGAL_MODULES_DIR}/CGAL_parse_version_h.cmake")
 cgal_parse_version_h( "${CGAL_INSTALLATION_PACKAGE_DIR}/include/CGAL/version.h"