Proposed update to makefiles: Move wwwconf.h and xmlparse.h include files

Based on Luc Van Eycken's comments [1] on the location of the include
files, I propose that we do the following:

1) move the wwwconf.h file to {prefix}/include instead of
{prefix}/include/w3c-libwww
2) move the xmlparse.h file to {prefix}/include/w3c-libwww instead of
{prefix}/include

Also, as a follow up on [2], I have uncommented the check for the libICE
in configure as it is not needed anywhere.

The diffs are included below - any objections?

[1] http://lists.w3.org/Archives/Public/www-lib/1999AprJun/0138.html
[2] http://lists.w3.org/Archives/Public/www-lib/1999AprJun/0172.html

-- 
Henrik Frystyk Nielsen, <frystyk@w3.org>
World Wide Web Consortium, MIT/LCS NE43-356
545 Technology Square, Cambridge MA 02139, USA

Index: Makefile.am
===================================================================
RCS file: /sources/public/libwww/Makefile.am,v
retrieving revision 1.36
diff -r1.36 Makefile.am
24c24,25
< # We need to install the config.h header file as well
---
> # We need to install the config.h header file as well. As this file
> # is platform specific, we do not install it with the other libwww include files
27,28c28,29
< 	$(mkinstalldirs) $(pkgincludedir)
< 	$(INSTALL_DATA) $(top_builddir)/$(CONFIG_HEADER) $(pkgincludedir)/$(CONFIG_HEADER);
---
> 	$(mkinstalldirs) $(includedir)
> 	$(INSTALL_DATA) $(top_builddir)/$(CONFIG_HEADER) $(includedir)/$(CONFIG_HEADER);
Index: libwww-config.in
===================================================================
RCS file: /sources/public/libwww/libwww-config.in,v
retrieving revision 1.5
diff -r1.5 libwww-config.in
48c48
<       echo -I@includedir@/@PACKAGE@ @DEFS@
---
>       echo -I@includedir@ -I@includedir@/@PACKAGE@ @DEFS@
Index: configure.in
===================================================================
RCS file: /sources/public/libwww/configure.in,v
retrieving revision 1.80
diff -r1.80 configure.in
116c116
< AC_CHECK_LIB(ICE, IceConnectionNumber)
---
> dnl AC_CHECK_LIB(ICE, IceConnectionNumber)
Index: modules/expat/xmlparse/Makefile.am
===================================================================
RCS file: /sources/public/libwww/modules/expat/xmlparse/Makefile.am,v
retrieving revision 1.4
diff -r1.4 Makefile.am
20c20
< include_HEADERS = \
---
> pkginclude_HEADERS = \