Idiom was to check if variable is present and also set to 'true', but indeed, I got your point.
Other solution I had in mind was:
: {$MAKE_DTBS?} && make dtbs
but has the slighty drawback of printing error messages if MAKE_DTBS is not set, and am not able to suppress that, and MAKE_DTBS can be set to whatever value.
Idiom was to check if variable is present and also set to 'true', but indeed, I got your point.
Other solution I had in mind was:
: {$MAKE_DTBS?} && make dtbs
but has the slighty drawback of printing error messages if MAKE_DTBS is not set, and am not able to suppress that, and MAKE_DTBS can be set to whatever value.