diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
index 9befa2b..6e09788 100644
--- a/scripts/kconfig/conf.c
+++ b/scripts/kconfig/conf.c
@@ -3,6 +3,8 @@
  * Released under the terms of the GNU GPL v2.0.
  */
 
+#define _XOPEN_SOURCE 700
+
 #include <ctype.h>
 #include <stdlib.h>
 #include <stdio.h>
diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
index d292b46..d3f69f8 100644
--- a/scripts/kconfig/mconf.c
+++ b/scripts/kconfig/mconf.c
@@ -8,6 +8,8 @@
  * i18n, 2005, Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  */
 
+#define _XOPEN_SOURCE 700
+
 #include <sys/ioctl.h>
 #include <sys/wait.h>
 #include <ctype.h>
@@ -18,6 +20,7 @@
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h> /* for strcasecmp */
 #include <termios.h>
 #include <unistd.h>
 #include <locale.h>