Integrate perlio:

[ 14515]
Minor Encode tweaks:
- move Encode.pm back to top of Encode like normal XS extension
- avoid .def as a file extension (Win32 builds)

p4raw-link: @14515 on //depot/perlio: 023d8852d6bde0330d0722ae3a1239d17f22b192

p4raw-id: //depot/perl@14516

diff --cc ext/Encode/compile
Simple merge