Both the Msys2 and Cygwin runtimes make use of
FILE_DISPOSITON_POSIX_SEMANTICS in their implementations of the unlink()
system call. This enables these routines to behave similarly to POSIX where are
unlisted from the directory, if handles are still open.

https://github.com/msys2/msys2-runtime/blob/msys2-3.4.3/winsup/cygwin/syscalls.cc#L722
https://www.cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/syscalls.cc#l724Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>