Buildproblems on OSX 10.3 due to libxml2

Hi

As you might (or might not ;-) ) have noticed, there where no nightly pgadmin-trunk builds
for a few weeks now. The build broke because of problems with libxml2. I solved this now
by adding a custom-built libxml2 to my buildserver and passing --with-libxml2=<my inst dir>
to configure. The funny thing, however, is that OSX seems to include a version of libxml,
installed in /usr. This version was detected by configure before I installed my own version,
but since it doesn't include xmlwriter.h (I don't know why - An older version maybe?), the
build later failed.

Since this will plague more people than me, I'd suggest changing the configure-check for
libxml2 to explicitly check for xmlwriter.h.

greetings, Florian Pflug

Here is the relevant output of ./configure and make:
--------------------- configure ---------------------------------------
checking PostgreSQL in /Users/pgadmin3/Installs/PostgreSQL/8.1.0... ok
checking wxWidgets in /Users/pgadmin3/Installs/wxMac/2.6.2... ok
checking libxml2 in /usr... ok
<snipped output about creating makefiles>
PostgreSQL directory: /Users/pgadmin3/Installs/PostgreSQL/8.1.0
PostgreSQL pg_config binary: /Users/pgadmin3/Installs/PostgreSQL/8.1.0/bin/pg_config
PostgreSQL version: PostgreSQL 8.1.0

wxWidgets directory: /Users/pgadmin3/Installs/wxMac/2.6.2
wxWidgets wx-config binary: /Users/pgadmin3/Installs/wxMac/2.6.2/bin/wx-config
wxWidgets version: wxWidgets 2.6.2

Building a debug version of pgAdmin: No
Statically linking pgAdmin: Yes
Building a Mac OS X appbundle: Yes

---------------------- make ---------------------------------------
cd . && /bin/sh /Users/pgadmin3/BuildRoots/pgadmin3-trunk/config/missing --run autoheader
rm -f stamp-h1
touch config.h.in
cd . && /bin/sh ./config.status config.h
config.status: creating config.h
config.status: config.h is unchanged
make all-recursive
Making all in i18n
make[2]: Nothing to be done for `all'.
Making all in src
if g++ -DHAVE_CONFIG_H -I. -I. -I.. -Wall -Wno-non-virtual-dtor -I../src/include -I../src/agent/include -I../src/slony/include -I/Users/pgadmin3/Installs/PostgreSQL/8.1.0/include -DSSL
-I/Users/pgadmin3/Installs/wxMac/2.6.2/lib/wx/include/mac-unicode-release-static-2.6 -I/Users/pgadmin3/Installs/wxMac/2.6.2/include/wx-2.6 -D__WXMAC__ -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES
-DNO_GCC_PRAGMA -O2 -no-cpp-precomp -fno-rtti -I/usr/include/libxml2 -Wall -Wno-non-virtual-dtor -I../src/include -I../src/agent/include -I../src/slony/include -MT pgAdmin3.o -MD -MP -MF
".deps/pgAdmin3.Tpo" -c -o pgAdmin3.o `test -f './pgAdmin3.cpp' || echo './'`./pgAdmin3.cpp; \
then mv -f ".deps/pgAdmin3.Tpo" ".deps/pgAdmin3.Po"; else rm -f ".deps/pgAdmin3.Tpo"; exit 1; fi
In file included from ../src/include/frmQuery.h:17,
from pgAdmin3.cpp:52:
../src/include/favourites.h:19:30: libxml/xmlwriter.h: No such file or directory
In file included from ../src/include/frmQuery.h:17,
from pgAdmin3.cpp:52:
../src/include/favourites.h:62: error: `xmlTextWriterPtr' was not declared in
this scope
../src/include/favourites.h:62: error: parse error before `)' token
make[2]: *** [pgAdmin3.o] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2