diff --git a/configure b/configure
index c987491..f29c3c1 100755
--- a/configure
+++ b/configure
@@ -1,4 +1,5 @@
 #!/bin/bash
+test "${AS:-:}" = ":" && unset AS
 
 if test x"$1" = x"-h" -o x"$1" = x"--help" ; then
 cat <<EOF