Integrate perlio:

[  8021]
Various attempts at MSVC debug - not sure what has
changed but works now.
Seems atexit() _may_ work for DLLs built with MSVC so don't
call cleanup that way.

[  8019]
Add useperlio to config.vc
Turn off binmode in config_H.PL
Regen all the config_H.xx
Attempt to get debugging build with MSVC.

[  8018]
Test various dup/external program options on all platforms.

[  8017]
Fix harness to be less picky

p4raw-link: @8021 on //depot/perlio: be696b0a6b61315b71a751e7291be8d8a9066650
p4raw-link: @8019 on //depot/perlio: 8c8a4ace7996843229b7a1f2a007f1cea5c7a38d
p4raw-link: @8018 on //depot/perlio: e4a4387cd67b57d9dfcb057f769a33143eec0663
p4raw-link: @8017 on //depot/perlio: 252585246f39d85ad7388d28c06dd6ed97b4d47d

p4raw-id: //depot/perl@8022

diff --cc perlio.c
Simple merge