Integrate perlio:

[  7755]
Add dummy crlf layer (just as buffer)
Correct 1st bug - one layer of indirection.

[  7754]
Work-round to Perl_deb_nocontext is no longer required

[  7753]
diff -se shows these as different

[  7752]
Configure GCC/Win32 build -Duseperlio
Fix a couple of gross issues
- double-include of ../deb.o in re.dll
- win32sck.c needs PerlIO and FILE

[  7751]
Special case :crlf and :raw in dummy PerlIO_apply_layers

[  7750]
Missing aTHX_

p4raw-link: @7755 on //depot/perlio: 66ecd56be076649bc9da523c12d89e06e353e801
p4raw-link: @7754 on //depot/perlio: 29befd70e124b0c2d1673e9ffa4f201bfa81073b
p4raw-link: @7753 on //depot/perlio: 39fb0ac880fd9390e3f92048baaba9392e38eca6
p4raw-link: @7752 on //depot/perlio: 8fada4f68b93131e799325ac5c6f8a949351407d
p4raw-link: @7751 on //depot/perlio: 95c70f2077ea14f8e2426dbcac9828b259a86bf2
p4raw-link: @7750 on //depot/perlio: d6efbbad1ae8d76e90821a7418ba77645896b8bf

p4raw-id: //depot/perl@7756