Integrate changes #9493,9494,9495,9496 from maintperl

Integrate changes #9493,9494,9495,9496 from maintperl
into mainline.

fix a broken workaround for Borland compiler in change#4739
(caused weird "short reads" on DATA, which caused op/misc.t to fail)

nits spotted by Borland compiler

avoid redefinition warnings under Borland 5.02

various nits identified by the Borland 5.5 compiler; remove suppression
of a few warnings

p4raw-link: @9496 on //depot/maint-5.6/perl: 9d05ad52b0aa7d1f7d147da0c4dbc14de5fe4a37
p4raw-link: @9495 on //depot/maint-5.6/perl: 759997f1e719f33541bed70dd7f79bfa26a930b3
p4raw-link: @9494 on //depot/maint-5.6/perl: 01b59bde1cb7ff62776f3b83c0f2575c79a950a6
p4raw-link: @9493 on //depot/maint-5.6/perl: eea7051a8d4ef81c032143ab3193bc1240ab2e8f
p4raw-link: @4739 on //depot/perl: c39cd00800303e8967294e98aa4c427a1872a251

p4raw-id: //depot/perl@9497
p4raw-integrated: from //depot/maint-5.6/perl@9492 'merge in' sv.c
	utf8.h (@9288..) toke.c (@9292..) ext/File/Glob/bsd_glob.c
	(@9415..) win32/makefile.mk (@9426..) win32/win32.h (@9494..)