尝试在CMake中添加SDL2_mixer和SDL2作为ExternalProject

我目前正试图在我的CMake项目中获取SDL2和SDL2_混频器作为外部项目。

SDL2似乎可以正常工作,但我不能编译SDL2_mixer。当尝试链接 playwav 二元的。问题是 CFLAGS 和 LDFLAGS 中的变量 ExternalProject_Add . 在没有CMake的情况下从命令行生成时添加这些变量也会出现同样的问题。

这是我目前的代码:

cmake_minimum_required(VERSION 2.8)

include(ExternalProject)

project(sdl2_test)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall")
set(LIBS_DIR ${PROJECT_BINARY_DIR}/libs)
set(SDL2_VER "2.0.8")
set(SDL2_MIXER_VER "2.0.2")

# SDL library
ExternalProject_Add(sdl2_project
    URL http://www.libsdl.org/release/SDL2-${SDL2_VER}.tar.gz
    PREFIX ${LIBS_DIR}/SDL2
    INSTALL_COMMAND ""
)

ExternalProject_Get_Property(sdl2_project SOURCE_DIR)
ExternalProject_Get_Property(sdl2_project BINARY_DIR)

set(SDL2_SRC ${SOURCE_DIR})
set(SDL2_BIN ${BINARY_DIR})

file(GLOB SDL2_INCLUDE "${SDL2_SRC}/include/*")
file(COPY ${SDL2_INCLUDE} DESTINATION ${SDL2_BIN}/include/)

# SDL_mixer library
ExternalProject_Add(sdl2_mixer_project
    URL https://www.libsdl.org/projects/SDL_mixer/release/SDL2_mixer-${SDL2_MIXER_VER}.tar.gz
    DEPENDS sdl2_project
    PREFIX ${LIBS_DIR}/SDL2_mixer
    CONFIGURE_COMMAND
        SDL2_CONFIG=${SDL2_BIN}/sdl2-config
        CFLAGS=-I${SDL2_BIN}/include
        LDFLAGS=-L${SDL2_BIN}
        #LIBS=-ldl
        <SOURCE_DIR>/configure
            --prefix=<INSTALL_DIR>
            --enable-shared=no
            #--with-sdl-prefix=${SDL2_BIN}
            --disable-sdltest
    BUILD_COMMAND make
    INSTALL_COMMAND ""
)

#file(GLOB SDL2_INCLUDE "${SDL2_SRC}/include/*")
#file(COPY ${SDL2_INCLUDE} DESTINATION ${SDL2_BIN}/include/)

ExternalProject_Get_Property(sdl2_mixer_project SOURCE_DIR)
ExternalProject_Get_Property(sdl2_mixer_project BINARY_DIR)

set(SDL2_MIXER_SRC ${SOURCE_DIR})
set(SDL2_MIXER_BIN ${BINARY_DIR})

include_directories(${SDL2_SRC}/include)
include_directories(${SDL2_MIXER_SRC}/include)

set(SOURCE sdl2test.cc)
add_executable(sdl_test ${SOURCE})
add_dependencies(sdl_test sdl2_project sdl2_mixer_project)

target_link_libraries(sdl_test ${SDL2_BIN}/libSDL2.a)

文件 sdl2test.cc 只是一个虚拟文件:

#include <iostream>

int main()
{
    std::cout << "Hooray" << std::endl;
    return 0;
}