On Windows co-operative programs can be expected to open LLD's
output in FILE_SHARE_DELETE mode. This allows us to delete the
file (by moving it to a temporary filename and then deleting
it) so that we can link another output file that overwrites
the existing file, even if the current file is in use.
A similar strategy is documented here:
https://boostgsoc13.github.io/boost.afio/doc/html/afio/FAQ/deleting_open_files.html
Differential Revision: https://reviews.llvm.org/D82567
Ben Dunbobbin