iOS and tvOS use the same printf family as macOS, and these all have been available on macOS for a long time.
Closes #1868 (closed)
On macOS:
$ grep 'printf.*runs' _builddir/meson-logs/meson-log.txt
Checking if "C99 vsnprintf" runs: YES
Checking if "C99 snprintf" runs: YES
Checking if "Unix98 printf positional parameters" runs: YES
We should probably backport this to 2.64