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* `make` is changed from an alias to a function. This allows many CI scripts
  to be simplified, since they will no longer require `shopt expand_aliases`.
  It also allows us to be `source`d from within a subshell, when 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).

Version 1.47. Tagged as 'Env-1_47'