src: ensure O_CLOEXEC is defined on Windows
src: ensure O_CLOEXEC is defined on Windows

Windows uses _O_NOINHERIT as the name for its O_CLOEXEC
equivalent. Define O_CLOEXEC to match this to fix
portability when we remove GNULIB.

Reviewed-by: Pavel Hrdina <d4772d05997b8abf035041e3b4f4996380ea7e7a@redhat.com>
Signed-off-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

fabianfreyer/libvirt,libvirt/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,olafhering/libvirt,crobinso/libvirt,zippy2/libvirt,zippy2/libvirt,nertpinx/libvirt,olafhering/libvirt,zippy2/libvirt,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,libvirt/libvirt,nertpinx/libvirt,crobinso/libvirt,crobinso/libvirt,olafhering/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,libvirt/libvirt,olafhering/libvirt,nertpinx/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jardasgit/libvirt,nertpinx/libvirt,jardasgit/libvirt,jfehlig/libvirt