diff --git luit-clean/configure.ac luit-workdir/configure.ac
index c214d85..ba7b129 100644
--- luit-clean/configure.ac
+++ luit-workdir/configure.ac
@@ -59,10 +59,10 @@ case $host_os in
     darwin*)
         OS_CFLAGS=
         ;;
-    linux*)
+    linux* | astral*)
         AC_CHECK_HEADERS([poll.h])
         AC_CHECK_FUNCS([poll])
-        OS_CFLAGS="-D_XOPEN_SOURCE=500"
+        OS_CFLAGS="-D_XOPEN_SOURCE=600"
         ;;
     *)
         AC_CHECK_HEADERS([poll.h])