diff --git a/commands.c b/commands.c
index 2f8a2fe..b1f73ed 100644
--- a/commands.c
+++ b/commands.c
@@ -16,9 +16,6 @@
  * along with sxiv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#define _POSIX_C_SOURCE 200112L
-#define _IMAGE_CONFIG
-
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -29,6 +26,8 @@
 #include "options.h"
 #include "thumbs.h"
 #include "util.h"
+
+#define _IMAGE_CONFIG
 #include "config.h"
 
 void cleanup(void);
diff --git a/image.c b/image.c
index da46cab..4f49107 100644
--- a/image.c
+++ b/image.c
@@ -16,9 +16,6 @@
  * along with sxiv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#define _POSIX_C_SOURCE 200112L
-#define _IMAGE_CONFIG
-
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
@@ -27,6 +24,8 @@
 #include "image.h"
 #include "options.h"
 #include "util.h"
+
+#define _IMAGE_CONFIG
 #include "config.h"
 
 #if HAVE_LIBEXIF
diff --git a/main.c b/main.c
index f5b5158..3ab7b2c 100644
--- a/main.c
+++ b/main.c
@@ -16,9 +16,6 @@
  * along with sxiv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#define _POSIX_C_SOURCE 200112L
-#define _MAPPINGS_CONFIG
-
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
@@ -41,6 +38,8 @@
 #include "thumbs.h"
 #include "util.h"
 #include "window.h"
+
+#define _MAPPINGS_CONFIG
 #include "config.h"
 
 enum {
diff --git a/options.c b/options.c
index 403785c..882ac49 100644
--- a/options.c
+++ b/options.c
@@ -16,9 +16,6 @@
  * along with sxiv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#define _POSIX_C_SOURCE 200112L
-#define _IMAGE_CONFIG
-
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ -26,6 +23,8 @@
 
 #include "options.h"
 #include "util.h"
+
+#define _IMAGE_CONFIG
 #include "config.h"
 
 options_t _options;
diff --git a/thumbs.c b/thumbs.c
index d08e972..949dac9 100644
--- a/thumbs.c
+++ b/thumbs.c
@@ -16,9 +16,6 @@
  * along with sxiv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#define _POSIX_C_SOURCE 200112L
-#define _THUMBS_CONFIG
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -29,6 +26,8 @@
 
 #include "thumbs.h"
 #include "util.h"
+
+#define _THUMBS_CONFIG
 #include "config.h"
 
 #if HAVE_LIBEXIF
diff --git a/util.c b/util.c
index 4c09e97..17f40ec 100644
--- a/util.c
+++ b/util.c
@@ -16,8 +16,6 @@
  * along with sxiv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#define _POSIX_C_SOURCE 200112L
-
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
diff --git a/window.c b/window.c
index ec6cc04..f0929ac 100644
--- a/window.c
+++ b/window.c
@@ -16,9 +16,6 @@
  * along with sxiv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#define _POSIX_C_SOURCE 200112L
-#define _WINDOW_CONFIG
-
 #include <stdlib.h>
 #include <string.h>
 #include <locale.h>
@@ -28,9 +25,11 @@
 #include "options.h"
 #include "util.h"
 #include "window.h"
-#include "config.h"
 #include "icon/data.h"
 
+#define _WINDOW_CONFIG
+#include "config.h"
+
 enum {
 	H_TEXT_PAD = 5,
 	V_TEXT_PAD = 1