在ArchLinux上交叉编译Windows平台Drogon框架C++ HTTP服务器遇阻

在ArchLinux上使用Drogon框架编译面向Windows的C++ HTTP服务器，已安装mingw64系列工具，参考CMake交叉编译文档配置了工具链，但添加-DCMAKE_TOOLCHAIN_FILE参数执行CMake时，find_package()无法找到Drogon包。本地用clang++编译（不指定工具链）完全正常。

主CMakeLists.txt代码 #

cmake_minimum_required(VERSION 3.5)
project(lru_server CXX)

include(CheckIncludeFileCXX)

check_include_file_cxx(any HAS_ANY)
check_include_file_cxx(string_view HAS_STRING_VIEW)
check_include_file_cxx(coroutine HAS_COROUTINE)
if (NOT "${CMAKE_CXX_STANDARD}" STREQUAL "")
    # Do nothing
elseif (HAS_ANY AND HAS_STRING_VIEW AND HAS_COROUTINE)
    set(CMAKE_CXX_STANDARD 20)
elseif (HAS_ANY AND HAS_STRING_VIEW)
    set(CMAKE_CXX_STANDARD 17)
else ()
    set(CMAKE_CXX_STANDARD 14)
endif ()

set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)

add_executable(${PROJECT_NAME} main.cpp)
target_include_directories(${PROJECT_NAME} PUBLIC
    lru_cache/
    endpoints/
)

target_sources( ${PROJECT_NAME} PUBLIC
    lru_cache/lru_cache.cpp
    endpoints/ApiController.cpp
)


find_package(Drogon CONFIG REQUIRED)
target_link_libraries(${PROJECT_NAME} PRIVATE Drogon::Drogon)


if (CMAKE_CXX_STANDARD LESS 17)
    # With C++14, use boost to support any, string_view and filesystem
    message(STATUS "use c++14")
    find_package(Boost 1.61.0 REQUIRED)
    target_link_libraries(${PROJECT_NAME} PUBLIC Boost::boost)
elseif (CMAKE_CXX_STANDARD LESS 20)
    message(STATUS "use c++17")
else ()
    message(STATUS "use c++20")
endif ()

aux_source_directory(controllers CTL_SRC)
aux_source_directory(filters FILTER_SRC)
aux_source_directory(plugins PLUGIN_SRC)
aux_source_directory(models MODEL_SRC)

drogon_create_views(${PROJECT_NAME} ${CMAKE_CURRENT_SOURCE_DIR}/views
                    ${CMAKE_CURRENT_BINARY_DIR})

target_include_directories(${PROJECT_NAME}
                           PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
                                   ${CMAKE_CURRENT_SOURCE_DIR}/models)
target_sources(${PROJECT_NAME}
               PRIVATE
               ${SRC_DIR}
               ${CTL_SRC}
               ${FILTER_SRC}
               ${PLUGIN_SRC}
               ${MODEL_SRC})

工具链文件（TC-mingw.cmake） #

# 目标操作系统名称
set(CMAKE_SYSTEM_NAME Windows)

# 指定C/C++编译器
set(CMAKE_C_COMPILER   x86_64-w64-mingw32-gcc)
set(CMAKE_CXX_COMPILER x86_64-w64-mingw32-g++)

# 目标环境路径
set(CMAKE_FIND_ROOT_PATH 
    /usr/x86_64-w64-mingw32    
    /usr/x86_64-w64-mingw32/lib
    /usr/lib
    /usr/lib/cmake
    /usr/lib/cmake/Drogon)

# 调整FIND_XXX()命令的默认行为：
# 在宿主机环境中搜索程序
# set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)

# 在目标环境中搜索头文件和库
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

执行的CMake命令 #

cmake -S /var/repo/lru_cpp_rest_server/lru_server -B /var/repo_build/lru_cpp_rest_server/build-lru_server-MinGW64 -DCMAKE_TOOLCHAIN_FILE=/var/repo/lru_cpp_rest_server/lru_server/TC-mingw.cmake

首次错误输出 #

[20:01:45] @archlinux bin$ cmake -S /var/repo/lru_cpp_rest_server/lru_server -B /var/repo_build/lru_cpp_rest_server/build-lru_server-MinGW64 -DCMAKE_TOOLCHAIN_FILE=/var/repo/lru_cpp_rest_server/lru_server/TC-mingw.cmake
CMake Warning (dev) at CMakeLists.txt:29 (target_sources):
  Policy CMP0076 is not set: target_sources() command converts relative paths
  to absolute.  Run "cmake --help-policy CMP0076" for policy details.  Use
  the cmake_policy command to set the policy and suppress this warning.

  An interface source of target "lru_server" has a relative path.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Error at CMakeLists.txt:42 (find_package):
  Could not find a package configuration file provided by "Drogon" with any
  of the following names:

    DrogonConfig.cmake
    drogon-config.cmake

  Add the installation prefix of "Drogon" to CMAKE_PREFIX_PATH or set
  "Drogon_DIR" to a directory containing one of the above files.  If "Drogon"
  provides a separate development package or SDK, be sure it has been
  installed.

核心问题 #

为何使用工具链后，系统中已安装的Drogon无法被找到？

更新内容 #

调整工具链配置后，新的CMake执行错误输出：

[22:19:01] alxndrklbk@archlinux bin$ cmake -S /var/repo/lru_cpp_rest_server/lru_server/ -B build-lru_server-MinGW-Debug -DCMAKE_TOOLCHAIN_FILE=/var/repo/lru_cpp_rest_server/lru_server/TC-mingw.cmake
-- The CXX compiler identification is GNU 12.2.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/x86_64-w64-mingw32-gcc - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Looking for C++ include any
-- Looking for C++ include any - found
-- Looking for C++ include string_view
-- Looking for C++ include string_view - found
-- Looking for C++ include coroutine
-- Looking for C++ include coroutine - not found
CMake Warning (dev) at CMakeLists.txt:29 (target_sources):
  Policy CMP0076 is not set: target_sources() command converts relative paths
  to absolute.  Run "cmake --help-policy CMP0076" for policy details.  Use
  the cmake_policy command to set the policy and suppress this warning.

  An interface source of target "lru_server" has a relative path.
This warning is for project developers.  Use -Wno-dev to suppress it.

-- Found Jsoncpp: /usr/x86_64-w64-mingw32/include  
CMake Error at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
  Could NOT find OpenSSL, try to set the path to OpenSSL root folder in the
  system variable OPENSSL_ROOT_DIR (missing: OPENSSL_CRYPTO_LIBRARY
  OPENSSL_INCLUDE_DIR)
Call Stack (most recent call 

内容的提问来源于stack exchange，提问作者Alexander Kolbeko