Executable System Includes, master branch (2022.04.22.)
Made the executable include directories be handled as "system include directories". Finally bringing the behaviour in sync with that of atlas_add_library(...)
and atlas_add_test(SOURCES...)
.
This shortcoming in the code was uncovered while looking at athena!52409 (closed) and athena!52385 (closed). This should fix ATEAM-826.