With permission from the main authors [1], most of the code has been
relicensed under the MIT license.
SPDX license identifiers are used so that the license headers in source
code files aren't too large.
Add CONTRIBUTORS.rst file.
[1] https://github.com/rednex/rgbds/issues/128
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
fatalerror() prints a given string to stdout and exits(5). It
cannot format text, so there was a string temptext used with
sprintf() to format text and pass it to fatalerror().
errx() can format text, and it prints to stderr.
As a bonus, this fixes the linking warnings from use of sprintf().
