Integrate:

Integrate:
[ 26983]
Add gv_fetchpvs, which uses STR_WITH_LEN to call gv_fetchpvn_flags.
Many strlen()s saved.

[ 27050]
Yet more instances of gv_fetchpv... that should be GV_ADD rather than
TRUE.
Convert two gv_fetchpvn_flags to gv_fetchpvs.

[ 27053]
gv_fetchpvn_flags ranks highly in the profile, and the ::/' scanning
loop is iterated over millions of times. Add a flag GV_NOTQUAL purely
as an optimisation, when the caller is passing in a string that is
known not to contain any package separators.
p4raw-link: @27053 on //depot/perl: fafc274c285207343d70f4a0d51c29a2f492863a
p4raw-link: @27050 on //depot/perl: 71315bf2ed5c47e3f417cdce95f41fe9b0da6b1f
p4raw-link: @26983 on //depot/perl: 5c1737d116a34c9fc2f84dad1ca8ff52ccdaaa64

p4raw-id: //depot/maint-5.8/perl@29809
p4raw-integrated: from //depot/perl@27053 'edit in' pp_sys.c (@26983..)
	gv.c (@27050..) 'merge in' gv.h (@26664..)
p4raw-integrated: from //depot/perl@27050 'edit in' pp_ctl.c (@26983..)
	doio.c (@27028..)
p4raw-integrated: from //depot/perl@26983 'edit in' pp_sort.c
	(@26675..) toke.c (@26901..) op.c (@26926..) perl.c (@26947..)
	util.c (@26979..) 'merge in' handy.h (@26901..)