diff --git a/main.c b/main.c
index 9b74b67..50f145e 100644
--- a/main.c
+++ b/main.c
@@ -1,5 +1,4 @@
-#define _XOPEN_SOURCE 700
-#define _POSIX_C_SOURCE 200112L
+#define _POSIX_C_SOURCE 200809L
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
diff --git a/pam.c b/pam.c
index cac95a8..b90d9e8 100644
--- a/pam.c
+++ b/pam.c
@@ -1,4 +1,4 @@
-#define _XOPEN_SOURCE 500
+#define _POSIX_C_SOURCE 200809L
 #include <pwd.h>
 #include <security/pam_appl.h>
 #include <stdbool.h>
diff --git a/password.c b/password.c
index 6138e1f..db8ecae 100644
--- a/password.c
+++ b/password.c
@@ -1,4 +1,3 @@
-#define _XOPEN_SOURCE 500
 #include <assert.h>
 #include <errno.h>
 #include <pwd.h>
diff --git a/render.c b/render.c
index fa8832b..cbd5d01 100644
--- a/render.c
+++ b/render.c
@@ -1,4 +1,3 @@
-#define _POSIX_C_SOURCE 199506L
 #include <math.h>
 #include <stdlib.h>
 #include <wayland-client.h>
diff --git a/shadow.c b/shadow.c
index f928eaa..b7b10a6 100644
--- a/shadow.c
+++ b/shadow.c
@@ -1,4 +1,4 @@
-#define _XOPEN_SOURCE
+#define _XOPEN_SOURCE // for crypt
 #include <pwd.h>
 #include <shadow.h>
 #include <stdbool.h>