autogen: Always abide --system

If we do ./autogen.sh && ./configure, then later try ./autogen.sh --system,
configure isn't invoked with the requested params. Instead
config.status --recheck is run.

autogen.sh

@@ -77,7 +77,7 @@ if test "x$OBJ_DIR" != x; then
     cd "$OBJ_DIR"
 fi
 
-if test -z "$*" && test -f config.status; then
+if test -z "$*" && test -z "$EXTRA_ARGS" && test -f config.status; then
     ./config.status --recheck
 else
     $srcdir/configure $EXTRA_ARGS "$@"