Integrate perlio:

[  8232]
Encode's Makefile.PL fix not good for dmake $(MAKEFILE) is set to -f Makefile
and fails to make '-f'. (Also handle case where xxxx.c files have not been deleted.)

[  8231]
"Compiled" encode build cleanup
- Makefile uses catfile $(MAKEFILE) etc. for platform issues.
- .c files do not export sub-tables

p4raw-link: @8232 on //depot/perlio: 8d7e77d666ed754d5cd34909a5f2a7dd48814e28
p4raw-link: @8231 on //depot/perlio: 14a8264b45de3d095eb6a74fa50f09ffad5aef3d

p4raw-id: //depot/perl@8233