Integrate mainline

p4raw-id: //depot/perlio@8294

diff --cc perl.c
Simple merge

diff --cc pp_hot.c
Simple merge

diff --cc pp_sys.c
Simple merge

diff --cc t/lib/encode.t
index 890be55,34527d7..280c2d0
--- 1/t/lib/encode.t
--- 2/t/lib/encode.t
+++ b/t/lib/encode.t
@@@ -91,12 -91,3 +91,12 @@@ foreach my $enc_eb (@ebcdic_sets
     }
   }
  
 +for $i (256,128,129,256)
 + {
 +  my $c = chr($i);
 +  my $s = "$c\n".sprintf("%02X",$i);
-   ok(Encode::valid_utf8($s),1,"concat to utf8 botched");
++  ok(Encode::valid_utf8($s),1,"concat of $i botched");
 +  Encode::utf8_upgrade($s);
-   ok(Encode::valid_utf8($s),1,"concat to utf8 botched");
++  ok(Encode::valid_utf8($s),1,"concat of $i botched");
 + }
 +