+SBCL="$SBCLRUNTIME --noinform --sysinit /dev/null --userinit /dev/null --noprint --disable-debugger"
+
+# extract version and date
+VERSION=`$SBCL --eval '(write-line (lisp-implementation-version))' --eval '(sb-ext:quit)'`
+MONTH=`date "+%Y-%m"`
+
+sed -e "s/@VERSION@/$VERSION/" \
+ -e "s/@MONTH@/$MONTH/" < variables.template > variables.texinfo || exit 1
+