[Feature request] Allow specifying minimum ASDF version in a .asd file
I propose adding a new top-level form allowed in .asd files, preferably as the first form:
(require-version min &optional max)
MIN and MAX are version strings and represent the lower and upper bounds permitted. If MAX is NIL then the upper bounds check is skipped. If the ASDF version falls outside this interval then a user-friendly error will be signalled. This proposal is backwards-compatible, because older ASDF versions won't recognize the form and signal an error nevertheless (even though perhaps not user-friendly).