Support building on MS-Windows with libxml2.

 src/makefile.w32-in (OBJ2): Add xml.$(O).
 (GLOBAL_SOURCES): Add xml.c.
 ($(BLD)/xml.$(O)): New dependency list.
 src/xml.c (DEF_XML2_FN, LOAD_XML2_FN) [WINDOWSNT]: New macros.
 (fn_htmlReadMemory, fn_xmlReadMemory, fn_xmlDocGetRootElement)
 (fn_xmlFreeDoc, fn_xmlCleanupParser, fn_xmlCheckVersion)
 [!WINDOWSNT]: New macros.
 (init_libxml2_functions, libxml2_loaded_p): New functions.
 (parse_region): Call fn_xmlCheckVersion instead of using the macro
 LIBXML_TEST_VERSION.  Call libxml2 functions via the fn_* macros.
 (xml_cleanup_parser): New function, export for fn_xmlCleanupParser.
 Calls xmlCleanupParser only if libxml2 was loaded (or statically
 linked in).
 (Flibxml_parse_html_region, Flibxml_parse_xml_region): Call
 init_libxml2_functions before calling libxml2 functions.
 (syms_of_xml) <Qlibxml2_dll>: DEFSYM it.
 src/emacs.c: Don't include libxml/parser.h.
 (shut_down_emacs): Call xml_cleanup_parser, instead of calling
 xmlCleanupParser directly.
 src/ lisp.h [HAVE_LIBXML2]: Add prototype for xml_cleanup_parser.

 nt/configure.bat: Support building with libxml2.
 nt/INSTALL:
 nt/README.W32: Add information about libxml2.

 lisp/term/w32-win.el (dynamic-library-alist): Add libxml2 DLLs.

 lib-src/makefile.w32-in (obj): Add xml.o.

1 files changed, 34 insertions, 0 deletions

diff --git a/nt/INSTALL b/nt/INSTALL
index c470ed4960f..96ef52faf5e 100644
--- a/nt/INSTALL
+++ b/nt/INSTALL
@@ -367,6 +367,40 @@
   You can get pre-built binaries (including any required DLL and the
   header files) at http://sourceforge.net/projects/ezwinports/files/.
 
+* Optional libxml2 support
+
+  If configure.bat finds the libxml/HTMLparser.h file in the include path,
+  Emacs is built with libxml2 support by default; to avoid that you can
+  pass the argument --without-libxml2.
+
+  In order to support libxml2 at runtime, a libxml2-enabled Emacs must
+  be able to find the relevant DLLs during startup; failure to do so
+  is not an error, but libxml2 features won't be available to the
+  running session.
+
+  One place where you can get pre-built Windows binaries of libxml2
+  (including any required DLL and the header files) is here:
+
+     http://sourceforge.net/projects/ezwinports/files/
+
+  To compile Emacs with libxml2 from that site, you will need to pass
+  the "--cflags -I/path/to/include/libxml2" option to configure.bat,
+  because libxml2 header files are installed in the include/libxml2
+  subdirectory of the directory where you unzip the binary
+  distribution.  Other binary distributions might use other
+  directories, although include/libxml2 is the canonical place where
+  libxml2 headers are installed on Posix platforms.
+
+  You will also need to install the libiconv "development" tarball,
+  because the libiconv headers need to be available to the compiler
+  when you compile with libxml2 support.  A MinGW port of libiconv can
+  be found on the MinGW site:
+
+   http://sourceforge.net/projects/mingw/files/MinGW/Base/libiconv/
+
+  You need the libiconv-X.Y.Z-N-mingw32-dev.tar.lzma tarball from that
+  site.
+
 * Experimental SVG support
 
   SVG support is currently experimental, and not built by default.