Add a helper function for printing multi-line post-build messages on a
target. The message lines are joined with newlines, written to a file at
configure time, and printed at build time using a single cmake -E cat
command, replacing the need for repeated cmake -E echo invocations.
Signed-off-by: Frantisek Hrbata <frantisek.hrbata@espressif.com>
a0b0ee562a