Integrate mainline as of _55

p4raw-id: //depot/ansiperl@305

diff --cc op.c
Simple merge

diff --cc perl.h
index 724384f,0ffb04c..c05d4a9
--- 1/perl.h
--- 2/perl.h
+++ b/perl.h
@@@ -2301,6 -2309,6 +2309,10 @@@ EXT bool       numeric_local INIT(TRUE);    /
  #define PERL_SCRIPT_MODE "r"
  #endif
  
++#ifndef PERL_SCRIPT_MODE
++#define PERL_SCRIPT_MODE "r"
++#endif
++
  /*
   * nice_chunk and nice_chunk size need to be set
   * and queried under the protection of sv_mutex