Integrate:

[ 24223]
Make the four-argument form of select() return undef
instead of -1 on error.

[ 25418]
Revert change #24223 : select() will continue
to return -1 on error, like in previous versions, and
like other system builtins.

(ie a no-op)
p4raw-link: @25418 on //depot/perl: 4189264e895252d9336b503e6f64ea18c10701f6
p4raw-link: @24223 on //depot/perl: 5c477709a8f3aa3110d51ae872950c20ff14fed6

p4raw-id: //depot/maint-5.8/perl@25419
p4raw-integrated: from //depot/perl@25415 'edit in' pod/perlfunc.pod
	(@25414..)
p4raw-integrated: from //depot/perl@24223 'edit in' pp_sys.c (@24164..)