[CMake] install EXPORT uses absolute paths on Windows, making libraries not relocatable

[Wojciech Mamrak]

Hello,

based on both wiki and this presentation:
https://archive.fosdem.org/2013/schedule/event/moderncmake/attachments/slides/258/export/events/attachments/moderncmake/slides/258/cmake_fosdem_2013.pdf

I have made this simple example. Its purpose is to test installing
projects and importing them by other projects.


CMakeLists.txt:

cmake_minimum_required(VERSION 3.3)

add_library(foo main.cpp)

if (NOT DEFINED INSTALL_LIBDIR)
   set(INSTALL_LIBDIR "" CACHE PATH "Output directory for libraries")
endif()

set(CMAKECONFIG_INSTALL_DIR "${INSTALL_LIBDIR}/CMake")

include(CMakePackageConfigHelpers)

configure_package_config_file(FooConfig.cmake.in FooConfig.cmake
                              INSTALL_DESTINATION "${CMAKECONFIG_INSTALL_DIR}")

install(FILES "${CMAKE_CURRENT_BINARY_DIR}/FooConfig.cmake"
        DESTINATION "${CMAKECONFIG_INSTALL_DIR}")
install(TARGETS foo
        EXPORT FooTargets
        ARCHIVE DESTINATION "${INSTALL_LIBDIR}")
install(EXPORT FooTargets
        DESTINATION "${CMAKECONFIG_INSTALL_DIR}")


FooConfig.cmake.in:

@PACKAGE_INIT@

include("${CMAKE_CURRENT_LIST_DIR}/FooTargets.cmake")


Assume sources are located at "G:/workspace/Foo".
I am setting INSTALL_LIBDIR to "G:/Install". Installation output:
>  -- Install configuration: "Debug"
>  -- Installing: G:/Install/CMake/FooConfig.cmake
>  -- Installing: G:/Install/foo.lib
>  -- Installing: G:/Install/CMake/FooTargets.cmake
>  -- Installing: G:/Install/CMake/FooTargets-debug.cmake


The contents of FooTargets-debug.cmake seems to be problematic:

#----------------------------------------------------------------
# Generated CMake target import file for configuration "Debug".
#----------------------------------------------------------------

# Commands may need to know the format version.
set(CMAKE_IMPORT_FILE_VERSION 1)

# Import target "foo" for configuration "Debug"
set_property(TARGET foo APPEND PROPERTY IMPORTED_CONFIGURATIONS DEBUG)
set_target_properties(foo PROPERTIES
  IMPORTED_LINK_INTERFACE_LANGUAGES_DEBUG "CXX"
  IMPORTED_LOCATION_DEBUG "G:/Install/foo.lib"
  )

list(APPEND _IMPORT_CHECK_TARGETS foo )
list(APPEND _IMPORT_CHECK_FILES_FOR_foo "G:/Install/foo.lib" )

# Commands beyond this point should not need to know the version.
set(CMAKE_IMPORT_FILE_VERSION)


Notice the absolute paths, which make this code not relocatable. I
would like to be able to copy the install tree to some other machine
and point CMAKE_PREFIX_PATH to that new location. How can I achieve
this?

regards