Integrate changes #9511,9514,9517 from maintperl into mainline.

Integrate changes #9511,9514,9517 from maintperl into mainline.

README.win32 tweaks; add a note about alternative location for
getting a gcc-2.95.2 that will build perl properly on windows

add some notes about gutsy threading matters

many of the utilities interpolate literal paths within doublequotes
(fails on dosish platforms where path contains backslashes)

p4raw-link: @9517 on //depot/maint-5.6/perl: 541b948d383abe4f534f846ff692d582506919cf
p4raw-link: @9514 on //depot/maint-5.6/perl: c8c8f510c2814a9e3cbdb8e7ca306018e0f7c510
p4raw-link: @9511 on //depot/maint-5.6/perl: 58a9db026b6f67b774654d285ac34aceada86380

p4raw-id: //depot/perl@9518
p4raw-integrated: from //depot/maint-5.6/perl@9510 'copy in'
	utils/perldoc.PL x2p/find2perl.PL (@9312..) 'merge in'
	README.win32 (@9227..) x2p/s2p.PL (@9312..) pod/perlguts.pod
	(@9507..)