-test "$REQUIRED_AUTOCONF_VERSION" || REQUIRED_AUTOCONF_VERSION=2.53
-test "$REQUIRED_AUTOMAKE_VERSION" || REQUIRED_AUTOMAKE_VERSION=1.9
-test "$REQUIRED_LIBTOOL_VERSION" || REQUIRED_LIBTOOL_VERSION=1.5
-test "$REQUIRED_GETTEXT_VERSION" || REQUIRED_GETTEXT_VERSION=0.12
-test "$REQUIRED_GLIB_GETTEXT_VERSION" || REQUIRED_GLIB_GETTEXT_VERSION=2.2.0
-test "$REQUIRED_INTLTOOL_VERSION" || REQUIRED_INTLTOOL_VERSION=0.30
-test "$REQUIRED_PKG_CONFIG_VERSION" || REQUIRED_PKG_CONFIG_VERSION=0.14.0
-test "$REQUIRED_GTK_DOC_VERSION" || REQUIRED_GTK_DOC_VERSION=1.0
-test "$REQUIRED_DOC_COMMON_VERSION" || REQUIRED_DOC_COMMON_VERSION=2.3.0
-test "$REQUIRED_GNOME_DOC_UTILS_VERSION" || REQUIRED_GNOME_DOC_UTILS_VERSION=0.4.2
+REQUIRED_AUTOCONF_VERSION=${REQUIRED_AUTOCONF_VERSION:-2.53}
+REQUIRED_AUTOMAKE_VERSION=${REQUIRED_AUTOMAKE_VERSION:-1.9}
+REQUIRED_LIBTOOL_VERSION=${REQUIRED_LIBTOOL_VERSION:-1.4.3}
+REQUIRED_GETTEXT_VERSION=${REQUIRED_GETTEXT_VERSION:-0.10.40}
+REQUIRED_GLIB_GETTEXT_VERSION=${REQUIRED_GLIB_GETTEXT_VERSION:-2.2.0}
+REQUIRED_INTLTOOL_VERSION=${REQUIRED_INTLTOOL_VERSION:-0.25}
+REQUIRED_PKG_CONFIG_VERSION=${REQUIRED_PKG_CONFIG_VERSION:-0.14.0}
+REQUIRED_GTK_DOC_VERSION=${REQUIRED_GTK_DOC_VERSION:-1.0}
+REQUIRED_DOC_COMMON_VERSION=${REQUIRED_DOC_COMMON_VERSION:-2.3.0}
+REQUIRED_GNOME_DOC_UTILS_VERSION=${REQUIRED_GNOME_DOC_UTILS_VERSION:-0.4.2}