port: fix -Wdeprecated-declarations warning about sprintf on macOS clang 14

Remove uses of sprintf to fix this warning:

    warning: 'sprintf' is deprecated: This function is provided for
    compatibility reasons only.  Due to security concerns inherent in the
    design of sprintf(3), it is highly recommended that you use snprintf(3)
    instead. [-Wdeprecated-declarations]

Change-Id: Ifff3746c1cc4e51a8cf4c08ccd845c887d76c6be
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>