Integrate perlio:

[  7555]
Fix read from STDERR on raw unix layer for Solaris where fd 2 is
open RDWR so does not fail. (pragma/warnings 303 again...)

[  7554]
Fix case where ungetc(f,EOF) was allowed.
Move PerlIO_ungetc() near PerlIO_putc()/PerlIO_getc() in the file
so we can see similarities.
Use types more carefully and a STDCHAR array in hope that this will
fix Jarkko's 64bit machine.

p4raw-link: @7555 on //depot/perlio: 8f24bd7931e1129a30ea0a951e81eecafa42f53b
p4raw-link: @7554 on //depot/perlio: 313ca112ae76354c03e7aff0a3e35062e8173ef0

p4raw-id: //depot/perl@7558

diff --cc perlio.c
Simple merge