make is changed from an alias to a function. This allows many CI scripts
to be simplified, since they will no longer require shopt -s expand_aliases.
It also allows us to be source-d from within a subshell, where alias
definitions have no effect, which is useful in certain special cases.
mk function now uses trap to clean up whatever the manner in which it
is exited. It also runs in -e mode (and uses an OR operator to avoid
grep failures being considered fatal) so that mk behaves the same,
whether the calling shell was in -e mode or not. (This is useful because
CI scripts are run in -e mode by default.)
mk now builds the make arguments using an array, to avoid any issues
with special characters in any of the strings used.
Now passes ShellCheck tests.
Set correct tool options for cross-compiling Raspberry Pi ROMs (reflects
addition of Machine=RPi from Library-1_76).
