调用i686-w64-mingw32.static-cmake CMakeLists.txt然后make使用不使用任何外部库的程序，但是在尝试交叉编译 Windows 的 SDL 程序时会发生以下错误。
CMake 日志。
== Using MXE wrapper: /home/tp/ext-git/mxe/usr/bin/i686-w64-mingw32.static-cmake
- cmake version 3.20.1
- warnings for unused CMAKE_POLICY_DEFAULT variables can be ignored
== Using MXE toolchain: /home/tp/ext-git/mxe/usr/i686-w64-mingw32.static/share/cmake/mxe-conf.cmake
== Using MXE runresult: /home/tp/ext-git/mxe/usr/share/cmake/modules/TryRunResults.cmake
== Adding "-DCMAKE_BUILD_TYPE=Release"
loading initial cache file /home/tp/ext-git/mxe/usr/share/cmake/modules/TryRunResults.cmake
-- Configuring done
CMake Warning (dev) in CMakeLists.txt:
Policy CMP0111 is not set: An imported target missing its location property
fails during generation. Run "cmake --help-policy CMP0111" for policy
details. Use the cmake_policy command to set the policy and suppress this
warning.
IMPORTED_IMPLIB not set for imported target "SDL2::SDL2" configuration
"Release".
This warning is for project developers. Use -Wno-dev to suppress it.
-- Generating done
-- Build files have been written to: /home/tp/Desktop
犯错误。
CMakeFiles/untitled.dir/build.make:96: *** target pattern contains no '%'. Stop.
make[1]: *** [CMakeFiles/Makefile2:82: CMakeFiles/untitled.dir/all] Error 2
make: *** [Makefile:91: all] Error 2
我的CMakeLists.txt
cmake_minimum_required(VERSION 3.5)
project(untitled LANGUAGES CXX)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
find_package(SDL2 REQUIRED)
add_executable(untitled main.cpp)
target_link_libraries(untitled SDL2::SDL2)
同一个CMakeLists.txt文件在 *nix 上工作得很好，但在这里失败了。到底是怎么回事？
编辑
新的细节。
CMake 工具链文件。
# This file is part of MXE. See LICENSE.md for licensing information.
# https://cmake.org/cmake/help/latest
# Can't set `cmake_minimum_required` or `cmake_policy` in toolchain
# since toolchain is read before CMakeLists.txt
# See `target-cmake.in` for CMAKE_POLICY_DEFAULT_CMPNNNN
# Check if we are using mxe supplied version
# - toolchain is included multiple times so set a guard in
# environment to suppress duplicate messages
if(NOT ${CMAKE_COMMAND} STREQUAL /home/tp/ext-git/mxe/usr/x86_64-pc-linux-gnu/bin/cmake AND NOT DEFINED ENV{_MXE_CMAKE_TOOLCHAIN_INCLUDED})
message(WARNING "
** Warning: direct use of toolchain file is deprecated
** Please use prefixed wrapper script instead:
i686-w64-mingw32.static-cmake [options] <path-to-source>
- uses mxe supplied cmake version 3.20.1
- loads toolchain
- loads common run results
- sets various policy defaults
")
set(ENV{_MXE_CMAKE_TOOLCHAIN_INCLUDED} TRUE)
endif()
# Use CACHE variables to allow user setting with `-D`
# Use CACHE FORCE in rare cases of misconfigured CMakeLists.txt
# - e.g include(FindPkgConfig)
# https://github.com/mxe/mxe/issues/1023
# - projects may still set these in which case FORCE doesn't have
# any advantage, just causes inconvenience
# https://github.com/mxe/mxe/pull/1621#discussion_r106937505
# Use normal variables expected to be set by toolchain/system
# - projects should test for these values and not try to override
## General configuration
set(CMAKE_SYSTEM_NAME Windows)
set(CMAKE_SYSTEM_PROCESSOR i686 CACHE STRING "System Processor")
set(MSYS 1)
set(CMAKE_EXPORT_NO_PACKAGE_REGISTRY ON)
# Workaround for https://www.cmake.org/Bug/view.php?id=14075
set(CMAKE_CROSS_COMPILING ON)
## Library config
set(BUILD_SHARED_LIBS OFF CACHE BOOL "BUILD_SHARED_LIBS")
set(BUILD_STATIC_LIBS ON CACHE BOOL "BUILD_STATIC_LIBS")
set(BUILD_SHARED OFF CACHE BOOL "BUILD_SHARED")
set(BUILD_STATIC ON CACHE BOOL "BUILD_STATIC")
set(LIBTYPE STATIC)
## Paths etc.
# These MODEs shouldn't be changed by users, we only want headers/libs
# from cross-build and "never" want binaries. We do, however, want
# `*-config` scripts but there's no way to instruct cmake to do that.
#
# The best solution may be to whitelist utilities
# https://github.com/mxe/mxe/issues/1667
# and symlink them to an additional root path, changing PROGRAM to ONLY
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
# Allow user to specify list of locations to search
set(CMAKE_FIND_ROOT_PATH /home/tp/ext-git/mxe/usr/i686-w64-mingw32.static CACHE PATH "List of root paths to search on the filesystem")
set(CMAKE_PREFIX_PATH /home/tp/ext-git/mxe/usr/i686-w64-mingw32.static CACHE PATH "List of directories specifying installation prefixes to be searched")
set(CMAKE_INSTALL_PREFIX /home/tp/ext-git/mxe/usr/i686-w64-mingw32.static CACHE PATH "Installation Prefix")
# For custom mxe FindPackage scripts
set(CMAKE_MODULE_PATH "/home/tp/ext-git/mxe/usr/share/cmake/modules" ${CMAKE_MODULE_PATH})
# projects (mis)use `-isystem` to silence warnings from 3rd-party
# source (among other things). gcc6 introduces changes to search
# order which breaks this usage.
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129
# https://gitlab.kitware.com/cmake/cmake/issues/16291
# https://gitlab.kitware.com/cmake/cmake/issues/16919
set(CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES /home/tp/ext-git/mxe/usr/i686-w64-mingw32.static/include)
set(CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES /home/tp/ext-git/mxe/usr/i686-w64-mingw32.static/include)
## Programs
set(CMAKE_C_COMPILER /home/tp/ext-git/mxe/usr/bin/i686-w64-mingw32.static-gcc)
set(CMAKE_CXX_COMPILER /home/tp/ext-git/mxe/usr/bin/i686-w64-mingw32.static-g++)
set(CMAKE_Fortran_COMPILER /home/tp/ext-git/mxe/usr/bin/i686-w64-mingw32.static-gfortran)
set(CMAKE_RC_COMPILER /home/tp/ext-git/mxe/usr/bin/i686-w64-mingw32.static-windres)
# CMAKE_RC_COMPILE_OBJECT is defined in:
# <cmake root>/share/cmake-X.Y/Modules/Platform/Windows-windres.cmake
set(CPACK_NSIS_EXECUTABLE i686-w64-mingw32.static-makensis)
## Individual package configuration
file(GLOB mxe_cmake_files
"/home/tp/ext-git/mxe/usr/i686-w64-mingw32.static/share/cmake/mxe-conf.d/*.cmake"
)
foreach(mxe_cmake_file ${mxe_cmake_files})
include(${mxe_cmake_file})
endforeach()
和makefile的部分
# External object files for target untitled
untitled_EXTERNAL_OBJECTS =
untitled.exe: CMakeFiles/untitled.dir/main.obj
untitled.exe: CMakeFiles/untitled.dir/build.make
untitled.exe: SDL2::SDL2-NOTFOUND
untitled.exe: CMakeFiles/untitled.dir/linklibs.rsp
untitled.exe: CMakeFiles/untitled.dir/objects1.rsp
untitled.exe: CMakeFiles/untitled.dir/link.txt
带有SDL2的行是目标模式错误的行。