-dnl Augeas (required)
-PKG_CHECK_MODULES([AUGEAS], [augeas])
-AC_SUBST([AUGEAS_CFLAGS])
-AC_SUBST([AUGEAS_LIBS])
+dnl libvirt (highly recommended)
+PKG_CHECK_MODULES([LIBVIRT], [libvirt],
+ [AC_SUBST([LIBVIRT_CFLAGS])
+ AC_SUBST([LIBVIRT_LIBS])
+ AC_DEFINE([HAVE_LIBVIRT],[1],[libvirt found at compile time.])
+ ],
+ [AC_MSG_WARN([libvirt not found, some core features will be disabled])])
+AM_CONDITIONAL([HAVE_LIBVIRT],[test "x$LIBVIRT_LIBS" != "x"])
+
+dnl libxml2 (highly recommended)
+PKG_CHECK_MODULES([LIBXML2], [libxml-2.0],
+ [AC_SUBST([LIBXML2_CFLAGS])
+ AC_SUBST([LIBXML2_LIBS])
+ AC_DEFINE([HAVE_LIBXML2],[1],[libxml2 found at compile time.])
+ ],
+ [AC_MSG_WARN([libxml2 not found, some core features will be disabled])])