Was building pgsql 8.3.8 from source on a new install of Centos 5.2,
and got this error from ./configure --with-libxml :
checking for xmlSaveToBuffer in -lxml2... no
configure: error: library 'xml2' (version >= 2.6.23) is required for XML support
But I had libxml2 v 2.6.26 or so installed. The real problem was that
libxml2-devel wasn't installed. No big deal, just thought I'd mention
it.