x86_64 assembly pack: keep making Windows build more robust.

PR: 2963 and a number of others

crypto/bn/asm/x86_64-mont.pl

@@ -40,7 +40,8 @@ $0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
 ( $xlate="${dir}../../perlasm/x86_64-xlate.pl" and -f $xlate) or
 die "can't locate x86_64-xlate.pl";
 
-open STDOUT,"| \"$^X\" $xlate $flavour $output";
+open OUT,"| \"$^X\" $xlate $flavour $output";
+*STDOUT=*OUT;
 
 # int bn_mul_mont(
 $rp="%rdi";	# BN_ULONG *rp,

crypto/bn/asm/x86_64-mont5.pl

@@ -28,7 +28,8 @@ $0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
 ( $xlate="${dir}../../perlasm/x86_64-xlate.pl" and -f $xlate) or
 die "can't locate x86_64-xlate.pl";
 
-open STDOUT,"| \"$^X\" $xlate $flavour $output";
+open OUT,"| \"$^X\" $xlate $flavour $output";
+*STDOUT=*OUT;
 
 # int bn_mul_mont_gather5(
 $rp="%rdi";	# BN_ULONG *rp,