Make the list of valid distros show up also in slightly older Perl versions

See http://perldoc.perl.org/functions/readdir.html .

1 files changed, 1 insertions, 1 deletions

diff --git a/autogen.sh b/autogen.sh
index c83ad8c0b397..955d04ef5610 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -48,7 +48,7 @@ sub invalid_distro($$)
     print STDERR "valid values are:\n";
     my $dirh;
     opendir ($dirh, "distro-configs");
-    while (readdir ($dirh)) {
+    while (($_ = readdir ($dirh))) {
     /(.*)\.conf$/ || next;
     print STDERR "\t$1\n";
     }