Update CMake gates for 4.2 and fix CI toolchain paths

Author: Luohaothu

.github/workflows/Build.yml

@@ -111,11 +111,12 @@ jobs:
                   /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
                 fi
                 eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
-                brew install gcc@15
+                brew install gcc@15 binutils
                 GCC_HOME=$(brew --prefix gcc@15)
                 echo "CC=$GCC_HOME/bin/gcc-15" >> "$GITHUB_ENV"
                 echo "CXX=$GCC_HOME/bin/g++-15" >> "$GITHUB_ENV"
                 echo "$GCC_HOME/bin" >> "$GITHUB_PATH"
+                echo "$(brew --prefix binutils)/bin" >> "$GITHUB_PATH"
               fi
             else
               wget -q https://apt.llvm.org/llvm.sh
@@ -131,7 +132,7 @@ jobs:
               done
               echo "CC=clang-21" >> "$GITHUB_ENV"
               echo "CXX=clang++-21" >> "$GITHUB_ENV"
-              echo "CXXFLAGS=-stdlib=libc++" >> "$GITHUB_ENV"
+              echo "CXXFLAGS=-stdlib=libc++ -isystem /usr/include/c++/v1" >> "$GITHUB_ENV"
               echo "LDFLAGS=-stdlib=libc++" >> "$GITHUB_ENV"
             fi
           elif [ "$RUNNER_OS" == "macOS" ]; then

CMakeLists.txt

@@ -15,13 +15,18 @@
 # ----------------------------------------------------------------------------
 
 cmake_minimum_required(VERSION 4.0.2 FATAL_ERROR)
-# The specific value used for CMake==4.0.2
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-    # This specific value changes as experimental support evolves. See
-    # `Help/dev/experimental.rst` in the CMake source corresponding to
-    # your CMake build for the exact value to use.
-    "a9e1cf81-9932-4810-974b-6eccaf14e457")
-set(CMAKE_EXPERIMENTAL_EXPORT_BUILD_DATABASE 4bd552e2-b7fb-429a-ab23-c83ef53f3f13)
+# The specific values used for experimental CMake features.
+if(CMAKE_VERSION VERSION_GREATER_EQUAL "4.2")
+    set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD "d0edc3af-4c50-42ea-a356-e2862fe7a444")
+    set(CMAKE_EXPERIMENTAL_EXPORT_BUILD_DATABASE "73194a1d-c0b5-41b9-9190-a4512925e192")
+else()
+    set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
+        # This specific value changes as experimental support evolves. See
+        # `Help/dev/experimental.rst` in the CMake source corresponding to
+        # your CMake build for the exact value to use.
+        "a9e1cf81-9932-4810-974b-6eccaf14e457")
+    set(CMAKE_EXPERIMENTAL_EXPORT_BUILD_DATABASE 4bd552e2-b7fb-429a-ab23-c83ef53f3f13)
+endif()
 set(CMAKE_EXPORT_BUILD_DATABASE 1)
 
 # ----------------------------------------------------------------------------
@@ -41,9 +46,6 @@ project(opflow VERSION ${OPFLOW_VERSION} LANGUAGES C CXX)
 set(OPFLOW_VERSION_STRING "${OPFLOW_VERSION} - ${SHORT_SHA1} - ${GIT_CHANGE}")
 message(STATUS "Build opflow: ${OPFLOW_VERSION_STRING}")
 
-set(CMAKE_EXPERIMENTAL_EXPORT_BUILD_DATABASE 4bd552e2-b7fb-429a-ab23-c83ef53f3f13)
-set(CMAKE_EXPORT_BUILD_DATABASE 1)
-
 set(CMAKE_CXX_MODULE_STD 1)
 
 include(GNUInstallDirs)