An example CMake Visual Studio Project. Both user and software (find_package) can decide on using certain 3rd party external library. Add USE_XXX as macro in either CMakeLists.txt and C/C++ programs.

CMakeLists.txt

# CMakeList.txt : CMake project for test_cmake, include source and define
# project specific logic here.
#
cmake_minimum_required (VERSION 3.8)

project ("test_cmake")

# Find OpenMP package
find_package(OpenMP)

set(CMAKE_CXX_STANDARD 14)
set(CMAKE_CXX_STANDARD_REQUIRED True)

# needs to setup VCPKG_ROOT in PATH before continuing
message("VCPKG_ROOT:  " "$ENV{VCPKG_ROOT}")

set(SOFT_LIST "Boost;GSL;suitesparse;Armadillo;absl;TBB")
foreach(_LIB_ ${SOFT_LIST})
	message("===============================")
	string(TOUPPER ${_LIB_} _LIB_UP_)
	set(USE_FLAG USE_${_LIB_UP_})
	set(${USE_FLAG} TRUE CACHE BOOL "Use ${_LIB_} library")
	find_package(${_LIB_})
	if(${_LIB_}_FOUND)
		message(STATUS "${_LIB_} library is found; you may use ${_LIB_}")
		# if not empty, print variables
		foreach(VAR_SUF DIR;INCLUDE_DIRS;LIBRARY;LIBRARIES)
			if (NOT "${${_LIB_}_${VAR_SUF}}" STREQUAL "")
				MESSAGE(STATUS "  -- ${_LIB_}_${VAR_SUF}:")
				MESSAGE(STATUS "         " ${${_LIB_}_${VAR_SUF}})
			endif()
		endforeach()
	else()
		# set USE_FLAG to false
		set(${USE_FLAG} OFF CACHE BOOL "Use ${_LIB_} library" FORCE)
		MESSAGE(STATUS "  ${_LIB_} package was NOT found, it will not be used" )
	endif()
	message(STATUS "${USE_FLAG}: " "${${USE_FLAG}}")
	message("===============================")
endforeach()

message("===============================")
foreach(_LIB_ ${SOFT_LIST})
	string(TOUPPER ${_LIB_} _LIB_UP_)
	set(USE_FLAG USE_${_LIB_UP_})
	message(STATUS "${USE_FLAG}: " "${${USE_FLAG}}")
endforeach()
message("===============================")

# Add source to this project's executable.
add_executable (test_cmake "test_cmake.cpp" "test_cmake.h")

# TODO: Add tests and install targets if needed.
if(USE_ABSL)
	# add extra definition for CPP
	target_compile_definitions(test_cmake PRIVATE USE_ABSL)
	
	target_link_libraries(test_cmake PRIVATE absl::strings)
endif()

CMakePresets.json

{
    "version": 3,
    "configurePresets": [
        {
            "name": "windows-base",
            "hidden": true,
            "generator": "Ninja",
            "binaryDir": "${sourceDir}/out/build/${presetName}",
            "installDir": "${sourceDir}/out/install/${presetName}",
          "cacheVariables": {
            "CMAKE_C_COMPILER": "cl.exe",
            "CMAKE_CXX_COMPILER": "cl.exe",
            "CMAKE_TOOLCHAIN_FILE": {
              "value": "$env{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake",
              "type": "FILEPATH"
            }
          },
            "condition": {
                "type": "equals",
                "lhs": "${hostSystemName}",
                "rhs": "Windows"
            }
        },
        {
            "name": "x64-debug",
            "displayName": "x64 Debug",
            "inherits": "windows-base",
            "architecture": {
                "value": "x64",
                "strategy": "external"
            },
            "cacheVariables": {
              "CMAKE_BUILD_TYPE": "Debug"
            }
        },
        {
            "name": "x64-release",
            "displayName": "x64 Release",
            "inherits": "x64-debug",
            "cacheVariables": {
                "CMAKE_BUILD_TYPE": "Release"
            }
        }
    ]
}

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