The system headers on z/OS are in EBCDIC, but are untagged. The bi-m…

…odal build requires that files be tagged correctly

   so this patch copies the errno.h file (which may be mounted on a read-only file system) to a local file and then tags
   it as IBM-1047 (EBCDIC) so that it can be processed properly. The longer-term fix for this may be to have z/OS tag
   header files as EBCDIC, although this would not be something Perl could rely on for several years.