--- vile-9.7x.orig/aclocal.m4	2009-12-07 10:47:06.000000000 +1100
+++ vile-9.7x/aclocal.m4	2009-12-07 10:46:02.000000000 +1100
@@ -2113,6 +2113,7 @@
 AC_REQUIRE([AC_PROG_LEX])
 
 test -z "$LEX" && LEX=lex
+test "x$LEX" = "x:" && LEX=lex  # : is not a usable default
 AC_MSG_CHECKING(if $LEX is really flex)
 if ( $LEX '-?' </dev/null 2>&1 |fgrep flex >/dev/null )
 then