diff --git a/frontends/framebuffer/Makefile b/frontends/framebuffer/Makefile
index bdedd903b..9b03a111b 100644
--- a/frontends/framebuffer/Makefile
+++ b/frontends/framebuffer/Makefile
@@ -23,7 +23,6 @@ CFLAGS += '-DNETSURF_FB_FONT_FANTASY="$(NETSURF_FB_FONT_FANTASY)"'
 CFLAGS += -std=c99 -g -Dsmall \
 	  -D_BSD_SOURCE \
 	  -D_DEFAULT_SOURCE \
-	  -D_XOPEN_SOURCE=600 \
 	  -D_POSIX_C_SOURCE=200809L
 
 LDFLAGS += -lm
diff --git a/frontends/gtk/Makefile b/frontends/gtk/Makefile
index ec60ce70c..c19720f94 100644
--- a/frontends/gtk/Makefile
+++ b/frontends/gtk/Makefile
@@ -37,7 +37,6 @@ GTKCFLAGS := -std=c99 -Dgtk -Dnsgtk -g \
 		$(GTKDEPFLAGS) \
 		-D_BSD_SOURCE \
 		-D_DEFAULT_SOURCE \
-		-D_XOPEN_SOURCE=600 \
 		-D_POSIX_C_SOURCE=200809L \
 		-D_NETBSD_SOURCE \
 		-DGTK_RESPATH=\"$(NETSURF_GTK_RES_PATH)\"
diff --git a/frontends/monkey/Makefile b/frontends/monkey/Makefile
index 86f1d912e..6604a88a5 100644
--- a/frontends/monkey/Makefile
+++ b/frontends/monkey/Makefile
@@ -12,7 +12,6 @@ CWARNFLAGS += -Werror
 CFLAGS += -std=c99 -Dmonkey -Dnsmonkey -g \
 	  -D_BSD_SOURCE \
 	  -D_DEFAULT_SOURCE \
-	  -D_XOPEN_SOURCE=700 \
 	  -D_POSIX_C_SOURCE=200809L \
 	  -D_NETBSD_SOURCE \
 	  -DMONKEY_RESPATH=\"$(NETSURF_MONKEY_RESOURCES)\"
diff --git a/utils/dirent.h b/utils/dirent.h
index fa78e1491..318734c30 100644
--- a/utils/dirent.h
+++ b/utils/dirent.h
@@ -28,8 +28,8 @@
  *  utils config header include.
  */
 
-#ifndef _NETSURF_UTILS_DIRENT_H_
-#define _NETSURF_UTILS_DIRENT_H_
+#ifndef NETSURF_UTILS_DIRENT_H
+#define NETSURF_UTILS_DIRENT_H
 
 #include "utils/config.h"