Integrate changes #9538,9539 from maintperl into mainline.

Integrate changes #9538,9539 from maintperl into mainline.

fflush() is a macro on SunOS 4.1.x, so provide a wrapper
for use with _fwalk() (fix for change#7705)

another tweak needed for SunOS 4.1.x build (from Mike Guy)
(cp -f is not portable)

p4raw-link: @9539 on //depot/maint-5.6/perl: 3da0943717409aa5209a9776746cc2cfeb50eb29
p4raw-link: @9538 on //depot/maint-5.6/perl: 741daf9fefb369fa97f8467fc06d60a8832dcdee
p4raw-link: @7705 on //depot/perl: 74cac757131a44f884c4728708d3a2e5d87b32d3

p4raw-id: //depot/perl@9540
p4raw-integrated: from //depot/maint-5.6/perl@9536 'merge in' util.c
	(@9288..) Makefile.SH (@9312..)