Update to libxml2 2.9.4 by merging commit 'd8083bf7' into klp-dev.

Bug: 32956747
Change-Id: I04c5bdea11733cc8dab6244f4a1bf33f0ff66277
(cherry-picked from 312a2fc2f0200bbb187771f25e08ed5afd447e40)
diff --git a/include/libxml/xmlversion.h b/include/libxml/xmlversion.h
index 1264867..321d5eb 100644
--- a/include/libxml/xmlversion.h
+++ b/include/libxml/xmlversion.h
@@ -29,28 +29,28 @@
  *
  * the version string like "1.2.3"
  */
-#define LIBXML_DOTTED_VERSION "2.9.1"
+#define LIBXML_DOTTED_VERSION "2.9.2"
 
 /**
  * LIBXML_VERSION:
  *
  * the version number: 1.2.3 value is 10203
  */
-#define LIBXML_VERSION 20901
+#define LIBXML_VERSION 20902
 
 /**
  * LIBXML_VERSION_STRING:
  *
  * the version number string, 1.2.3 value is "10203"
  */
-#define LIBXML_VERSION_STRING "20901"
+#define LIBXML_VERSION_STRING "20902"
 
 /**
  * LIBXML_VERSION_EXTRA:
  *
  * extra version information, used to show a CVS compilation
  */
-#define LIBXML_VERSION_EXTRA "-GITv2.9.1"
+#define LIBXML_VERSION_EXTRA "-GITv2.9.2-48-g4b31d61"
 
 /**
  * LIBXML_TEST_VERSION:
@@ -58,7 +58,7 @@
  * Macro to check that the libxml version in use is compatible with
  * the version the software has been compiled against
  */
-#define LIBXML_TEST_VERSION xmlCheckVersion(20901);
+#define LIBXML_TEST_VERSION xmlCheckVersion(20902);
 
 #ifndef VMS
 #if 0
@@ -435,7 +435,7 @@
  */
 
 #ifndef LIBXML_ATTR_ALLOC_SIZE
-# if ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)))
+# if (!defined(__clang__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3))))
 #  define LIBXML_ATTR_ALLOC_SIZE(x) __attribute__((alloc_size(x)))
 # else
 #  define LIBXML_ATTR_ALLOC_SIZE(x)