gnu: libxml2: Add fix for CVE-2016-1762.

* gnu/packages/patches/libxml2-CVE-2016-1762.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/xml.scm (libxml2/fixed)[source]: Add patch.

gnu/local.mk

@@ -633,6 +633,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/libwmf-CVE-2015-0848+CVE-2015-4588.patch	\
   %D%/packages/patches/libwmf-CVE-2015-4695.patch		\
   %D%/packages/patches/libwmf-CVE-2015-4696.patch		\
+  %D%/packages/patches/libxml2-CVE-2016-1762.patch		\
   %D%/packages/patches/libxslt-CVE-2015-7995.patch		\
   %D%/packages/patches/lirc-localstatedir.patch			\
   %D%/packages/patches/libpthread-glibc-preparation.patch	\

gnu/packages/patches/libxml2-CVE-2016-1762.patch

@@ -0,0 +1,31 @@
+Copied from Debian.
+
+From a7a94612aa3b16779e2c74e1fa353b5d9786c602 Mon Sep 17 00:00:00 2001
+From: Daniel Veillard <veillard@redhat.com>
+Date: Tue, 9 Feb 2016 12:55:29 +0100
+Subject: [PATCH] Heap-based buffer overread in xmlNextChar
+
+For https://bugzilla.gnome.org/show_bug.cgi?id=759671
+
+when the end of the internal subset isn't properly detected
+xmlParseInternalSubset should just return instead of trying
+to process input further.
+
+[carnil: drop patches to testsuite files]
+---
+
+diff --git a/parser.c b/parser.c
+index c5741e3..0677030 100644
+--- a/parser.c
++++ b/parser.c
+@@ -8468,6 +8468,7 @@ xmlParseInternalSubset(xmlParserCtxtPtr ctxt) {
+      */
+     if (RAW != '>') {
+ 	xmlFatalErr(ctxt, XML_ERR_DOCTYPE_NOT_FINISHED, NULL);
++	return;
+     }
+     NEXT;
+ }
+-- 
+2.8.1
+

gnu/packages/xml.scm

@@ -116,7 +116,8 @@ (define libxml2/fixed
                              version ".tar.gz"))
          (sha256
           (base32
-           "0g336cr0bw6dax1q48bblphmchgihx9p1pjmxdnrd6sh3qci3fgz")))))))
+           "0g336cr0bw6dax1q48bblphmchgihx9p1pjmxdnrd6sh3qci3fgz"))
+         (patches (search-patches "libxml2-CVE-2016-1762.patch")))))))
 
 (define-public python-libxml2
   (package (inherit libxml2)