Upgrade to expat 2.1.0.

From http://www.libexpat.org/:

Release 2.1.0 includes security & other bug fixes, new features, and updated build support.

Security fixes

* Memory leak in poolGrow (CVE-2012-1148)
* Resource leak in readfilemap.c (CVE-2012-1147)
* Hash DOS attack (CVE-2012-0876)
* Buffer over-read and crash in big2_toUtf8 (CVE-2009-3560)
* Parser crash with special UTF-8 sequences (CVE-2009-3270)

New features

* Added function XML_SetHashSalt that allows setting an initial value (salt) for hash calculations (part of the fix for bug 3496608).
* When compiled with XML_ATTR_INFO defined, adds new API member XML_GetAttributeInfo() that allows retrieving the byte offsets for attribute names and values (patch 3446384).
* Added CMake build system (bug 2990652, patch 3312568).
* Added run-benchmark target to Makefile.in - relies on testdata module present in the same relative location as in the repository.

Bug fixes

* Harmful XML_ParserCreateNS suggestion (1742315)
* CVE-2012-1147 - Resource leak in readfilemap.c (2895533)
* Expat build fails on linux-amd64 with gcc version>=4.1 -O3 (1785430)
* Build modifications using autoreconf instead of buildconf.sh (1983953, 2517952, 2517962, 2649838)
* OBJEXT and EXEEXT support while building (2815947, 2884086)
* CVE-2009-3720 - Parser crash with special UTF-8 sequences (1990430)
* xmlwf should return non-zero exit status if not well-formed (2517938)
* Wrong statement about XMLDecl in xmlwf.1 and xmlwf.sgml (2517946)
* Dangling positionPtr after error (2855609)
* CVE-2009-3560 - Buffer over-read and crash in big2_toUtf8() (2894085)
* CVE-2012-1148 - Memory leak in poolGrow (2958794)
* UNEXPECTED_STATE with a trailing "%" in entity value (3010819)
* Unitialized memory returned from XML_Parse (3206497)
* make check fails on mingw-w64 (87849)

Change-Id: Ieb663fdfea82119918e245a714af533b58e0f7f5
diff --git a/README b/README
index fda282a..1f88467 100644
--- a/README
+++ b/README
@@ -1,5 +1,5 @@
 
-                        Expat, Release 2.0.1
+                        Expat, Release 2.1.0
 
 This is Expat, a C library for parsing XML, written by James Clark.
 Expat is a stream-oriented XML parser.  This means that you register
@@ -25,8 +25,7 @@
 If you are building Expat from a check-out from the CVS repository,
 you need to run a script that generates the configure script using the
 GNU autoconf and libtool tools.  To do this, you need to have
-autoconf 2.52 or newer and libtool 1.4 or newer (1.5 or newer preferred).
-Run the script like this:
+autoconf 2.58 or newer. Run the script like this:
 
         ./buildconf.sh
 
@@ -65,8 +64,8 @@
 the directories into which things will be installed.
 
 If you are interested in building Expat to provide document
-information in UTF-16 rather than the default UTF-8, follow these
-instructions (after having run "make distclean"):
+information in UTF-16 encoding rather than the default UTF-8, follow
+these instructions (after having run "make distclean"):
 
         1. For UTF-16 output as unsigned short (and version/error
            strings as char), run:
@@ -106,7 +105,10 @@
 environment, because variable-setting priority is
 1) commandline
 2) in-makefile
-3) environment           
+3) environment  
+
+Note: This only applies to the Expat library itself, building UTF-16 versions
+of xmlwf and the tests is currently not supported.         
 
 Note for Solaris users:  The "ar" command is usually located in
 "/usr/ccs/bin", which is not in the default PATH.  You will need to