Research CLDR v37's new measurement / unit representation options

CLDR v37 expands, among other things, the range of ways a locale can specify its preferences for what units to use and how to represent those units, e.g.

a program (or database) could use 1.88 meters internally, but then for person-height have that measurement convert to 6 foot 2 inches for en_US and to 188 centimeters for de_CH.

At present, QLocale only crudely supports a choice between SI and the en_US vs en_GB systems of archaic units. Refinements in how SI is expressed (e.g., in the example above, 1.88 m vs 188 cm) are potentially of general importance.
However, present users of QLocale::measurementSystem() or its type are predominantly propagation of such values to other potentially affected classes and relatively trivial uses such as whether to use "points" based on mm or inch in fonts, IIUC. So this is decidedly low priority.