cmake让add_subdirectory()的所有target生成到同一目录

问题描述和解决办法

整个项目包括： 库、测试程序，都是基于源码生成；测试程序肯定是executable类型了，而如果生成的库是SHARED类型，在windows下就是.dll（以及对应的.lib）文件。
执行测试程序时，出现"xxx.dll"找不到，其中"xxx.dll"是整个解决方案产生的那个共享库。

虽然可以手动复制xxx.dll到yyy.exe的目录，但是每次手动复制很低效。

通过在add_subdirectory()前设定:

set(LIBRARY_OUTPUT_PATH "${CMAKE_BINARY_DIR}")
set(EXECUTABLE_OUTPUT_PATH "${CMAKE_BINARY_DIR}")

就能够分别在CMAKE_BINARY_DIR/Debug或CMAKE_BINARY_DIR/Release下得到xxx.lib和yyy.exe在一块儿了。

例子：给opencv1.0.0添加cmake支持

根目录的CMakeLists.txt如下：

cmake_minimum_required(VERSION 3.13)

project(opencv_100)

add_definitions(
    -DCVAPI_EXPORTS
    -DHAVE_JPEG
    -DHAVE_PNG
    -DHAVE_TIFF
    -DHAVE_JASPER
)

include_directories(
    "cv/include"
    "cv/src"
    "cxcore/Include"
    "cvaux/include"
    "otherlibs/highgui"
    "otherlibs/_graphics/include"
)

link_directories("otherlibs/_graphics/lib")
set(LIBRARY_OUTPUT_PATH "${CMAKE_BINARY_DIR}")
set(EXECUTABLE_OUTPUT_PATH "${CMAKE_BINARY_DIR}")


if (CMAKE_SYSTEM_NAME MATCHES "Windows")
    #message("inside windows")
    # add SAFESEH to Visual Studio. copied from http://www.reactos.org/pipermail/ros-diffs/2010-November/039192.html
    #if(${_MACHINE_ARCH_FLAG} MATCHES X86) # fails
    #message("inside that branch")
    
    # in VS2013, there is: fatal error LNK1104: cannot open file "LIBC.lib"
    # so, we have to add /NODEFAULTLIB:LIBC.LIB
    # reference: https://stackoverflow.com/questions/6016649/cannot-open-file-libc-lib
    set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /SAFESEH:NO /NODEFAULTLIB:LIBC.LIB") 
    set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} /SAFESEH:NO /NODEFAULTLIB:LIBC.LIB")
    set (CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} /SAFESEH:NO /NODEFAULTLIB:LIBC.LIB")
    #endif()
endif (CMAKE_SYSTEM_NAME MATCHES "Windows")



add_subdirectory("cxcore")

add_subdirectory("cv")

add_subdirectory("cvaux")

add_subdirectory("otherlibs/highgui")

add_subdirectory("samples")

# add_subdirectory("ml")
# add_subdirectory("otherlibs/cvcam")