Integrate changes #8677,8680,8681,8725,8732,8776,8782,9290

Integrate changes #8677,8680,8681,8725,8732,8776,8782,9290
from maintperl into mainline: perlport updates.

p4raw-link: @8732 on //depot/maint-5.6/perl: 90f80d9daeb9997573212370cc442fdb12c2aa97
p4raw-link: @8725 on //depot/maint-5.6/perl: e7a9bdc155196b4f612a787f76da7521b35f2e66
p4raw-link: @8681 on //depot/maint-5.6/perl: b572fec36f5c53c5a9c3496f89515a61e073fe81
p4raw-link: @8680 on //depot/maint-5.6/perl: f2214cd0e8376fbc371483c7957aef88a7eafbfd
p4raw-link: @8677 on //depot/maint-5.6/perl: 9bc1a4975d1d72fa279effb064305b9a4c210a71

p4raw-id: //depot/perl@9629
p4raw-edited: from //depot/maint-5.6/perl@9628 'edit in'
	pod/perlport.pod (@9227..)