CMake: How do I change properties on subdirectory project targets?

Question

I'm trying to organize the targets in my subproject (in this case poco), but I've come to find that properties can't be modified for ALIAS targets. I want the targets in my external project to be in their own folder, instead of sprawled out everywhere in the project tree (say the visual studio generator). Is there an easier way to add projects with my own properties?

So instead of:

- CMakePredefinedTargets
    - ALL_BUILD
    - INSTALL
    - ...
- MyTargets
    - SomeLibrary
    - SomeExe
- CppUnit
- Crypto
- Data
- ...

I want:

- CMakePredefinedTargets
    - ALL_BUILD
    - INSTALL
    - ...
- MyTargets
    - SomeLibrary
    - SomeExe
- Poco
    - CppUnit
    - Crypto
    - Data
    - ...

My attempt:

function(add_subdirectory_with_folder folder_name)
    function(add_library name type)
    _add_library(${ARGV})

    set_target_properties(${name}
        PROPERTIES
        FOLDER "${folder_name}"
    )
    endfunction()
    add_subdirectory(${ARGN})
endfunction()

# External Libs
add_subdirectory_with_folder("Poco" libs/poco)

Example target from the poco library:

add_library( "${LIBNAME}" ${LIB_MODE} ${SRCS} )
add_library( "${POCO_LIBNAME}" ALIAS "${LIBNAME}")
set_target_properties( "${LIBNAME}"
    PROPERTIES
    VERSION ${SHARED_LIBRARY_VERSION} SOVERSION ${SHARED_LIBRARY_VERSION}
    OUTPUT_NAME ${POCO_LIBNAME}
    DEFINE_SYMBOL JSON_EXPORTS
    )

My goal is to make it so I don't have to fork and maintain my own versions of libraries that I want to use just for quality of life tweaks. Is there a different method I can use to organize the project tree for IDEs? I know externalproject_add exists, but I do not think this has the facilities I am looking for. I will be adding other projects in the future in the form of git-submodules, but depending on if there is an easier method for this I'll explore other avenues.

EDIT:

To clarify, I'm already using a separate CMakeLists.txt for each module of my own project, plus a top level CMakeLists.txt which ties them all together, as well as collecting external libraries that my targets rely on. I want to modify the targets of external libraries without having to fork and maintain them myself just so I have nice folder structures in visual studio, xcode, or others. Linux obviously doesn't matter as much since most editing tools are folder based already.

Answer 1

https://github.com/andry81/tacklelib
https://github.com/andry81/tacklelib/blob/trunk/cmake/tacklelib/Project.cmake

cmake_minimum_required(VERSION 3.14)

# enable project folders
set_property(GLOBAL PROPERTY USE_FOLDERS ON)

## cmake builtin search paths and includes

LIST(APPEND CMAKE_MODULE_PATH "${TACKLELIB_CMAKE_ROOT}")

include(tacklelib/Project)
include(tacklelib/EnableTargetsExtension)

project(MyApp)

set(MYLIB_ROOT ...)

# somewhere at the end ...

## project folders

tkl_set_target_folder(CMAKE_CURRENT_LIST_DIR . * .       UTILITY     . util)
tkl_set_target_folder(CMAKE_CURRENT_LIST_DIR . * "tests" EXECUTABLE  . exe)
tkl_set_target_folder(CMAKE_CURRENT_LIST_DIR . * .       "SHARED_LIBRARY;STATIC_LIBRARY" . lib)

tkl_set_target_folder(MYLIB_ROOT * * .       UTILITY     . _3dparty/utility/mylib/util)
tkl_set_target_folder(MYLIB_ROOT * * "tests" EXECUTABLE  . _3dparty/utility/mylib/exe)
tkl_set_target_folder(MYLIB_ROOT * * .       "SHARED_LIBRARY;STATIC_LIBRARY" . _3dparty/utility/mylib/lib)
tkl_set_target_folder(MYLIB_ROOT * "tests" . * . _3dparty/utility/mylib/tests)

CMake command line:

cmake.exe -G "..." "-DTACKLELIB_CMAKE_ROOT=.../_externals/tacklelib/cmake" ...

Project directory structure:

...
_externals/
_out/
include/
src/
CMakeLists.txt

_out - directory with cmake cache and output

Solution layout:

_3dparty
  utility
    mylib
      lib
        mylib
CMakePredefinedTargets
  ALL_BUILD
  INSTALL
  ZERO_CHECK
exe
  myapp
util
  bundle