myos export prints every setting the requested stacks declare, in one process:
68 variables in half a second, where asking for them one at a time costs a
process each and about ten seconds.
The shim reads that once and includes it, so a .mk target sees
HOST_FABIO_VERSION and the computed fabio tag without make knowing anything
about how they are produced. --make quotes the values so make neither expands
a $ nor starts a comment at a #.
