feat(build): TBB 发现增加 multiarch 回退探测，并行 STL 接入系统 TBB

- apt 安装 libtbb-dev 后，conda cmake 仍找不到 TBBConfig.cmake
  （不搜索 /usr/lib/x86_64-linux-gnu/cmake）：顶层 find_package(TBB)
  未命中时回退 find_file 探测 Debian multiarch cmake 目录并设置 TBB_DIR
- parallel_stl 消费 TBB 头文件沿用 numa 的 shim 模式：TBB::tbb 携带的
  /usr/include 在 sysroot 工具链下会被 CMake 剥掉、强加则遮蔽工具链
  自身头文件，故将 tbb/ 与 oneapi/ 子树软链到 build/tbb-headers
- 实测（8M floats，16 核）：par 4.42x / par_unseq 4.54x vs plain loop；
  conda gcc 15 与系统 g++ 13 两条工具链均验证，109 项测试全通过

Author: LessUp

CMakeLists.txt

@@ -58,6 +58,18 @@ endif()
 # libstdc++. Without it the parallel STL example still builds and covers
 # seq/unseq; par policies are compiled in only when TBB is present.
 find_package(TBB QUIET)
+if(NOT TBB_FOUND)
+    # Fallback probe: conda-distributed CMake does not search the Debian
+    # multiarch cmake-config directory where apt installs TBBConfig.cmake.
+    find_file(HPC_TBB_CONFIG_FILE TBBConfig.cmake PATHS
+        /usr/lib/x86_64-linux-gnu/cmake/TBB
+        /usr/lib64/cmake/TBB
+        /usr/lib/cmake/TBB)
+    if(HPC_TBB_CONFIG_FILE)
+        get_filename_component(TBB_DIR "${HPC_TBB_CONFIG_FILE}" DIRECTORY)
+        find_package(TBB QUIET)
+    endif()
+endif()
 if(TBB_FOUND)
     message(STATUS "TBB found: parallel STL example includes par/par_unseq")
 endif()

examples/03-modern-cpp/CMakeLists.txt

@@ -30,10 +30,30 @@ hpc_add_example(
 # Parallel STL execution policies. seq/unseq always build; par/par_unseq
 # require Intel TBB (GCC libstdc++ implements them on top of it).
 if(TBB_FOUND)
+    # TBB headers reach the targets through a shim directory, mirroring the
+    # numa pattern: TBB::tbb's /usr/include is silently dropped by CMake on
+    # sysroot toolchains (conda) and would shadow the toolchain's own
+    # headers if forced. Symlinking only the tbb/ and oneapi/ subtrees keeps
+    # the rest of the include resolution untouched.
+    get_target_property(_hpc_tbb_includes TBB::tbb INTERFACE_INCLUDE_DIRECTORIES)
+    set(_hpc_tbb_shim "${CMAKE_BINARY_DIR}/tbb-headers")
+    file(MAKE_DIRECTORY "${_hpc_tbb_shim}")
+    foreach(_hpc_tbb_inc ${_hpc_tbb_includes})
+        foreach(_hpc_tbb_sub tbb oneapi)
+            if(EXISTS "${_hpc_tbb_inc}/${_hpc_tbb_sub}"
+               AND NOT EXISTS "${_hpc_tbb_shim}/${_hpc_tbb_sub}")
+                execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink
+                    "${_hpc_tbb_inc}/${_hpc_tbb_sub}"
+                    "${_hpc_tbb_shim}/${_hpc_tbb_sub}")
+            endif()
+        endforeach()
+    endforeach()
+
     hpc_add_example(
         NAME parallel_stl
         SOURCES src/parallel_stl.cpp
         BENCHMARK_SOURCES bench/parallel_stl_bench.cpp
+        INCLUDE_DIRS ${_hpc_tbb_shim}
         LIBRARIES TBB::tbb
     )
     target_compile_definitions(parallel_stl PRIVATE HPC_HAS_TBB)