feat: Allow building with system libs by default (#1566)

As it stands, the Acts build system will pull quite a bit of software from the internet, and turning this behaviour off entirely currently involves setting quite a number of flags. This commit adds a new CMake option, `ACTS_USE_SYSTEM_LIBS`, which makes using a system installation the default for all dependencies.

CMakeLists.txt

@@ -25,25 +25,27 @@ option(ACTS_BUILD_EVERYTHING "Build with most options enabled (except HepMC3 and
 # core related options
 set(ACTS_PARAMETER_DEFINITIONS_HEADER "" CACHE FILEPATH "Use a different (track) parameter definitions header")
 option(ACTS_FORCE_ASSERTIONS "Force assertions regardless of build type" OFF)
+# external library options
+option(ACTS_USE_SYSTEM_LIBS "Use system libraries by default" OFF)
 # plugins related options
 option(ACTS_BUILD_PLUGIN_AUTODIFF "Build the autodiff plugin" OFF)
-option(ACTS_USE_SYSTEM_AUTODIFF "Use autodiff provided by the system instead of the bundled version" OFF)
+option(ACTS_USE_SYSTEM_AUTODIFF "Use autodiff provided by the system instead of the bundled version" ${ACTS_USE_SYSTEM_LIBS})
 option(ACTS_SETUP_ACTSVG "Build ActSVG display plugin" OFF)
-option(ACTS_USE_SYSTEM_ACTSVG "Use the ActSVG system library" OFF)
+option(ACTS_USE_SYSTEM_ACTSVG "Use the ActSVG system library" ${ACTS_USE_SYSTEM_LIBS})
 option(ACTS_BUILD_PLUGIN_ACTSVG "Build SVG display plugin" OFF)
 option(ACTS_BUILD_PLUGIN_CUDA "Build CUDA plugin" OFF)
 option(ACTS_BUILD_PLUGIN_DD4HEP "Build DD4hep plugin" OFF)
 option(ACTS_BUILD_PLUGIN_EXATRKX "Build the Exa.TrkX plugin" OFF)
 option(ACTS_EXATRKX_ENABLE_ONNX "Build the Onnx backend for the exatrkx plugin" OFF)
 option(ACTS_EXATRKX_ENABLE_TORCH "Build the torchscript backend for the exatrkx plugin" ON)
-option(ACTS_USE_SYSTEM_ACTSDD4HEP "Use the ActsDD4hep glue library provided by the system instead of building it" OFF)
+option(ACTS_USE_SYSTEM_ACTSDD4HEP "Use the ActsDD4hep glue library provided by the system instead of building it" ${ACTS_USE_SYSTEM_LIBS})
 option(ACTS_BUILD_PLUGIN_IDENTIFICATION "Build Identification plugin" OFF)
 option(ACTS_BUILD_PLUGIN_JSON "Build json plugin" OFF)
-option(ACTS_USE_SYSTEM_NLOHMANN_JSON "Use nlohmann::json provided by the system instead of the bundled version" OFF)
+option(ACTS_USE_SYSTEM_NLOHMANN_JSON "Use nlohmann::json provided by the system instead of the bundled version" ${ACTS_USE_SYSTEM_LIBS})
 option(ACTS_BUILD_PLUGIN_LEGACY "Build legacy plugin" OFF)
 option(ACTS_BUILD_PLUGIN_ONNX "Build ONNX plugin" OFF)
 option(ACTS_SETUP_VECMEM "Explicitly set up vecmem for the project" OFF)
-option(ACTS_USE_SYSTEM_VECMEM "Use a system-provided vecmem installation" OFF)
+option(ACTS_USE_SYSTEM_VECMEM "Use a system-provided vecmem installation" ${ACTS_USE_SYSTEM_LIBS})
 option(ACTS_BUILD_PLUGIN_SYCL "Build SYCL plugin" OFF)
 option(ACTS_BUILD_PLUGIN_TGEO "Build TGeo plugin" OFF)
 # fatras related options
@@ -60,7 +62,7 @@ option(ACTS_BUILD_EXAMPLES_GEANT4 "Build Geant4-based code in the examples" OFF)
 option(ACTS_BUILD_EXAMPLES_HEPMC3 "Build HepMC3-based code in the examples" OFF)
 option(ACTS_BUILD_EXAMPLES_PYTHIA8 "Build Pythia8-based code in the examples" OFF)
 option(ACTS_BUILD_EXAMPLES_PYTHON_BINDINGS "Build python bindings for the examples" OFF)
-option(ACTS_USE_SYSTEM_PYBIND11 "Use a system installation of pybind11" OFF )
+option(ACTS_USE_SYSTEM_PYBIND11 "Use a system installation of pybind11" ${ACTS_USE_SYSTEM_LIBS} )
 option(ACTS_USE_EXAMPLES_TBB "Use Threading Building Blocks library in examples" ON)
 option(ACTS_BUILD_ANALYSIS_APPS "Build Analysis applications in the examples" OFF)
 # test related options