&then &do
!copy_file config.&version&.def config.def -delete
&
-& NOTE: We must invoke Perl 5 not Perl 4. If necessary, edit the
-& next line to say "perl5 config.pl".
+& NOTE: We must invoke Perl 5 not Perl 4. The following
+& commands runs perl5 if it exists, otherwise runs perl,
+& in the hopes it is really perl5.
+&
+!attach_default_output (process_dir)>_where_perl ; &+
+ where_command perl5 ; detach_default_output
+&if (index (contents (process_dir)>_where_perl) 'perl5:') ^= 0
+&then !perl5 config.pl
+&else !perl config.pl
&
-!perl config.pl
!rename config.h.new config.&version&.h -delete
!delete_file config.def
&end