diff --git a/makefile b/makefile
index 774250f..e183781 100644
--- a/makefile
+++ b/makefile
@@ -4,6 +4,11 @@ CC=gcc
 #CC=tcc
 FLAGS=-std=c99 -pedantic -Wall -Werror=vla -Werror -g
 
+OS:=$(shell uname -s)
+ifeq ($(OS),Linux)
+	FLAGS+=-D_DEFAULT_SOURCE
+endif
+
 BIND=bin
 SRCD=src
 SUBD=sub
diff --git a/src/config.c b/src/config.c
index 2d1e733..6eeefbf 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1,4 +1,3 @@
-#define _XOPEN_SOURCE 700
 #include "config.h"
 #include "cylgom.h"
 #include "ini.h"
diff --git a/src/desktop.c b/src/desktop.c
index 6529373..e5c296d 100644
--- a/src/desktop.c
+++ b/src/desktop.c
@@ -1,4 +1,3 @@
-#define _XOPEN_SOURCE 700
 #include "desktop.h"
 #include "cylgom.h"
 #include "ini.h"
diff --git a/src/draw.c b/src/draw.c
index 3a84f7f..81d529d 100644
--- a/src/draw.c
+++ b/src/draw.c
@@ -1,4 +1,3 @@
-#define _XOPEN_SOURCE 700
 #include "draw.h"
 #include "cylgom.h"
 #include "termbox.h"
diff --git a/src/login.c b/src/login.c
index 6618a48..0e20c2c 100644
--- a/src/login.c
+++ b/src/login.c
@@ -1,6 +1,3 @@
-#define _XOPEN_SOURCE 700
-#define _DEFAULT_SOURCE
-
 #include "config.h"
 #include "login.h"
 #include "widgets.h"
diff --git a/src/util.c b/src/util.c
index fa8d9f8..bcfe1e1 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1,4 +1,3 @@
-#define _XOPEN_SOURCE 700
 #include "util.h"
 #include "config.h"
 #include "widgets.h"
diff --git a/src/widgets.c b/src/widgets.c
index 04b3109..fcffd0d 100644
--- a/src/widgets.c
+++ b/src/widgets.c
@@ -1,4 +1,3 @@
-#define _XOPEN_SOURCE 700
 #include "widgets.h"
 #include "cylgom.h"
 #include <string.h>