For https://bugzilla.gnome.org/show_bug.cgi?id=677606
For https://bugs.gentoo.org/show_bug.cgi?id=417539

If libxml2-2.8.0 is built with --with-icu --with-python on a system that has an
older version of libxml2 installed, then during "make install", libxml2mod.so
gets relinked to the systemwide version of libxml2.so.2 instead of libxml2.so.2
from the build tree, and fails at runtime if symbol versions from the older
libxml2.so.2 are not available. This effectively makes it impossible to build a
libxml2-2.8.0 binary package on a system that does not already have
libxml2-2.8.0 installed.

Investigation by Rafał Mużyło and Arfrever Frehtes Taifersar Arahesis revealed
the cause of the problem to be that libxml2's configure was adding ICU_LIBS to
LDFLAGS instead of to LIBADD. This resulted in GNU libtool using the wrong
argument order in its relinking command that gets run during "make install".