Config.pm: report perl path in version conflict.

When Config.pm dies with a perl/library version mismatch error, include
the path of the perl executable in the error message.

This helps avoid confusion during perl build when a cc wrapper written in
perl is used (such as colorgcc)

diff --git a/configpm b/configpm
index 87feab5..0f35309 100755 (executable)
--- a/configpm
+++ b/configpm
@@ -215,11 +215,11 @@ sub import {
     return;
 }
 
-die "Perl lib version (%s) doesn't match executable version ($])"
+die "Perl lib version (%s) doesn't match executable '$0' version ($])"
     unless $^V;
 
 $^V eq %s
-    or die "Perl lib version (%s) doesn't match executable version (" .
+    or die "Perl lib version (%s) doesn't match executable '$0' version (" .
        sprintf("v%%vd",$^V) . ")";
 
 ENDOFBEG