diff --git a/gnu-system.am b/gnu-system.am
index cd46753dcc..2a0a88f66a 100644
--- a/gnu-system.am
+++ b/gnu-system.am
@@ -254,6 +254,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/libtheora-config-guess.patch		\
   gnu/packages/patches/libtool-skip-tests.patch			\
   gnu/packages/patches/libtool-skip-tests-for-mips.patch	\
+  gnu/packages/patches/luit-posix.patch				\
   gnu/packages/patches/m4-gets-undeclared.patch			\
   gnu/packages/patches/m4-readlink-EINVAL.patch			\
   gnu/packages/patches/make-impure-dirs.patch			\
diff --git a/gnu/packages/patches/luit-posix.patch b/gnu/packages/patches/luit-posix.patch
new file mode 100644
index 0000000000..9a38c17a39
--- /dev/null
+++ b/gnu/packages/patches/luit-posix.patch
@@ -0,0 +1,15 @@
+See https://bugs.freedesktop.org/show_bug.cgi?id=47792;
+should become obsolete with the next release.
+
+diff -u luit-1.1.1.orig/sys.c luit-1.1.1/sys.c
+--- luit-1.1.1.orig/sys.c	2012-03-23 05:23:07.000000000 +0100
++++ luit-1.1.1/sys.c	2013-11-27 22:45:53.000000000 +0100
+@@ -20,6 +20,8 @@
+ THE SOFTWARE.
+ */
+ 
++#define _XOPEN_SOURCE 600
++
+ #ifdef HAVE_CONFIG_H
+ # include "config.h"
+ #endif
diff --git a/gnu/packages/xorg.scm b/gnu/packages/xorg.scm
index c3441d76c4..b81cc8acc3 100644
--- a/gnu/packages/xorg.scm
+++ b/gnu/packages/xorg.scm
@@ -1406,7 +1406,10 @@ tracking.")
                ".tar.bz2"))
         (sha256
           (base32
-            "0dn694mk56x6hdk6y9ylx4f128h5jcin278gnw2gb807rf3ygc1h"))))
+            "0dn694mk56x6hdk6y9ylx4f128h5jcin278gnw2gb807rf3ygc1h"))
+        ;; See https://bugs.freedesktop.org/show_bug.cgi?id=47792;
+        ;; should become obsolete with the next release.
+        (patches (list (search-patch "luit-posix.patch")))))
     (build-system gnu-build-system)
     (inputs
       `(("libfontenc" ,libfontenc)