Merge pull request #1226.

Remove dependency on Boost Test when not needed

.gitignore

@@ -17,7 +17,7 @@ quantlib.elc
 quantlib.pc
 QuantLib.spec
 CMakeCache.txt
-CMakeUserPresets.txt
+CMakeUserPresets.json
 Docs/.time-stamp
 Docs/.time-stamp-html
 Docs/.time-stamp-online

CMakeLists.txt

@@ -85,21 +85,6 @@ if (NOT DEFINED Boost_USE_STATIC_RUNTIME)
     set(Boost_USE_STATIC_RUNTIME ${MSVC})
 endif()
 
-# Boost thread and unit_test_framework needed for tests and benchmark
-find_package(Boost 1.58.0 REQUIRED COMPONENTS thread unit_test_framework)
-
-# Avoid using Boost auto-linking
-add_compile_definitions(BOOST_ALL_NO_LIB)
-
-if (QL_ENABLE_OPENMP)
-    find_package(OpenMP REQUIRED)
-endif()
-
-# Parallel test runner needs library rt on *nix for shm_open, etc.
-if (QL_ENABLE_PARALLEL_UNIT_TEST_RUNNER AND UNIX AND NOT APPLE)
-    find_library(RT_LIBRARY rt REQUIRED)
-endif()
-
 # Require C++11 or higher
 if (NOT DEFINED CMAKE_CXX_STANDARD)
     set(CMAKE_CXX_STANDARD 11)
@@ -114,6 +99,41 @@ if (NOT DEFINED CMAKE_CXX_EXTENSIONS)
     set(CMAKE_CXX_EXTENSIONS FALSE)
 endif()
 
+if (NOT DEFINED QL_BOOST_VERSION)
+    # Boost 1.75.0 or greater required for compiling with C++20
+    if (CMAKE_CXX_STANDARD GREATER_EQUAL 20)
+        set(QL_BOOST_VERSION 1.75.0)
+    else()
+        set(QL_BOOST_VERSION 1.58.0)
+    endif()
+endif()
+
+if (NOT DEFINED QL_BOOST_COMPONENTS)
+    # Boost thread and unit_test_framework needed for tests and benchmark
+    if (QL_BUILD_TEST_SUITE OR QL_BUILD_BENCHMARK)
+        set(QL_BOOST_COMPONENTS thread unit_test_framework)
+    else()
+        set(QL_BOOST_COMPONENTS thread)
+    endif()
+endif()
+
+find_package(Boost ${QL_BOOST_VERSION} REQUIRED COMPONENTS ${QL_BOOST_COMPONENTS})
+
+# Do not warn about Boost versions higher than 1.58.0
+set(Boost_NO_WARN_NEW_VERSIONS ON)
+
+# Avoid using Boost auto-linking
+add_compile_definitions(BOOST_ALL_NO_LIB)
+
+if (QL_ENABLE_OPENMP)
+    find_package(OpenMP REQUIRED)
+endif()
+
+# Parallel test runner needs library rt on *nix for shm_open, etc.
+if (QL_ENABLE_PARALLEL_UNIT_TEST_RUNNER AND UNIX AND NOT APPLE)
+    find_library(RT_LIBRARY rt REQUIRED)
+endif()
+
 # If available, use PIC for shared libs and PIE for executables
 if (NOT DEFINED CMAKE_POSITION_INDEPENDENT_CODE)
     set(CMAKE_POSITION_INDEPENDENT_CODE ON)