gnu: libx11: Update to 1.6.8.

* gnu/packages/xorg.scm (libx11): Update to 1.6.8.

gnu/packages/xorg.scm

@@ -5236,7 +5236,7 @@ draggable titlebars and borders.")
 (define-public libx11
   (package
     (name "libx11")
-    (version "1.6.7")
+    (version "1.6.8")
     (source
       (origin
         (method url-fetch)
@@ -5246,7 +5246,7 @@ draggable titlebars and borders.")
                ".tar.bz2"))
         (sha256
           (base32
-            "0j0k5bjz4kd7rx6z09n5ggxbzbi84wf78xx25ikx6jmsxwq9w3li"))))
+            "1mbkwhhprhf49s2iwx7kiliprsdvd690zk44x3h53ql9q52si2dj"))))
     (build-system gnu-build-system)
     (outputs '("out"
                "doc"))                            ;8 MiB of man pages + XML