setup: build exewrapper with Unicode support on py3
I didn't see a compiler switch documented anywhere, but I diffed the command
line for full VC++ project when toggling between MBCS and Unicode. This is all
they do.
#require execbit
$ hg init repo
$ cd repo
$ echo foo > foo
$ chmod 644 foo
$ hg ci -qAm '644'
$ chmod 755 foo
$ hg ci -qAm '755'
reverting to rev 0
$ hg revert -a -r 0
reverting foo
$ hg st
M foo
$ hg diff --git
diff --git a/foo b/foo
old mode 100755
new mode 100644
$ cd ..