Continuing from Marc's intriguing idea in the last thread, how would we
have portable syntax for hygienic keywords?

SRFI 177 keyword-call is just a portable stopgap measure; for a
language's native syntax, something like this is probably better:

(foo a b #:key1 c #:key2 d)

The question then arises: how do you make those hygienic?

Maybe like this:

(foo a b #:(hygienic key1) c #:(hygienic key2) d)

Or use a different prefix for hygienic and unhygienic keywords.