diff --git a/clar.c b/clar.c
index 12fa66d..f42ab45 100644
--- a/clar.c
+++ b/clar.c
@@ -5,6 +5,9 @@
  * For full terms see the included COPYING file.
  */
 
+#define _DARWIN_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+
 #include <errno.h>
 #include <setjmp.h>
 #include <stdlib.h>
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 4c9012d..7f2c1dc 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -28,8 +28,6 @@ target_sources(clar_test PRIVATE
 )
 target_compile_definitions(clar_test PRIVATE
 	CLAR_FIXTURE_PATH="${CMAKE_CURRENT_SOURCE_DIR}/resources/"
-	_DARWIN_C_SOURCE
-	_POSIX_C_SOURCE=200809L
 )
 target_compile_options(clar_test PRIVATE
 	$<IF:$<CXX_COMPILER_ID:MSVC>,/W4,-Wall>