make Config.pm report sane errors with older perls

p4raw-id: //depot/perl@5787

diff --git a/configpm b/configpm
index 19d0d71..c64af8a 100755 (executable)
--- a/configpm
+++ b/configpm
@@ -38,6 +38,9 @@ sub import {
 }
 
 ENDOFBEG_NOQ
+die "Perl lib version ($myver) doesn't match executable version (\$])"
+    unless \$^V;
+
 \$^V eq $myver
   or die "Perl lib version ($myver) doesn't match executable version (" .
     (sprintf "v%vd",\$^V) . ")";