Fix compilation on OS X

diff --git a/drd/tests/swapcontext.c b/drd/tests/swapcontext.c
index cfe0577a3d1dbe6d68989544265bb65c6791b0c7..cf600d4933f26fd398291e88e3da1af62b04cc3e 100644 (file)
--- a/drd/tests/swapcontext.c
+++ b/drd/tests/swapcontext.c
@@ -1,6 +1,7 @@
 /* See also https://bugs.kde.org/show_bug.cgi?id=432381. */
 
 #define _GNU_SOURCE
+#define _XOPEN_SOURCE
 
 #include <assert.h>
 #include <limits.h>