diff --git a/arch/posix/CMakeLists.txt b/arch/posix/CMakeLists.txt
index 9393a041b02..7001e54e75f 100644
--- a/arch/posix/CMakeLists.txt
+++ b/arch/posix/CMakeLists.txt
@@ -133,8 +133,6 @@ if (CONFIG_GPROF)
   target_link_options(native_simulator INTERFACE "-pg")
 endif()
 
-zephyr_compile_definitions(_POSIX_C_SOURCE=200809L _XOPEN_SOURCE=600 _XOPEN_SOURCE_EXTENDED)
-
 if (CONFIG_NATIVE_APPLICATION)
   zephyr_ld_options(
     -ldl
diff --git a/arch/posix/core/CMakeLists.txt b/arch/posix/core/CMakeLists.txt
index 3cf83c9fdda..12ec5261635 100644
--- a/arch/posix/core/CMakeLists.txt
+++ b/arch/posix/core/CMakeLists.txt
@@ -28,6 +28,8 @@ if(CONFIG_NATIVE_APPLICATION)
 		${ZEPHYR_BASE}/scripts/native_simulator/common/src/nce.c
 		${ZEPHYR_BASE}/scripts/native_simulator/common/src/nsi_host_trampolines.c
 	)
+
+	zephyr_library_compile_definitions(_POSIX_C_SOURCE=200809L _XOPEN_SOURCE=600 _XOPEN_SOURCE_EXTENDED)
 else()
 	zephyr_library_sources(
 		posix_core_nsi.c