[SOLVED] Is there a way to get -isystem for FetchContent targets?

Issue

NO_SYSTEM_FROM_IMPORTED tells us that IMPORTED targets automagically get -isystem. Does that also hold for targets introduced to the project with FetchContent?

If not (I assume so due to having problems with clang-tidy warnings on fetched targets), what is the best way to get -isystem for such targets?

Solution

It is actually really easy (kudos to @Tsyvarev):

include (FetchContent)

set (FETCHCONTENT_QUIET FALSE)

FetchContent_Declare (
  Catch2
  GIT_REPOSITORY https://github.com/catchorg/Catch2.git
  GIT_TAG v2.4.2
  GIT_PROGRESS TRUE
)

FetchContent_MakeAvailable (Catch2)

### here is what makes all include directories -isystem
get_target_property(CATCH2_IID Catch2 INTERFACE_INCLUDE_DIRECTORIES)
set_target_properties(Catch2 PROPERTIES INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${CATCH2_IID}")

Answered By - Florian Berchtold

Answer Checked By - Mary Flores (WPSolving Volunteer)