In rsync_options, use --delete-delay instead of --delete-after

[ryandesign (Ryan Carsten Schmidt)]

MacPorts base currently sets rsync_options "-rtzv --delete-after" in ./src/macports1.0/macports.tcl. --delete-delay is more efficient than --delete-after. We should test if the version of rsync in all versions of OS X MacPorts runs on supports using --delete-delay, and if so, use this instead.

[jmroot (Joshua Root)]

Apple's rsync doesn't appear to support this option even on Ventura.

% /usr/bin/rsync -av --delete-delay rtest1/ rtest2
rsync: --delete-delay: unknown option
rsync error: syntax or usage error (code 1) at /AppleInternal/Library/BuildRoots/d9889869-120b-11ee-b796-7a03568b17ac/Library/Caches/com.apple.xbs/Sources/rsync/rsync/main.c(1337) [client=2.6.9]