Many still import (chibi), and as (scheme base) is somewhat more
expensive to load at present these are changed to cond-expand.
Many libraries also rely on (srfi 33), and these have been changed
to a cond-expand first trying (srfi 60) where available.
Also fixing a few portability concerns (duplicate imports of the
same binding), and adding a few libraries missing from lib-tests.scm.
- Fixed some typos in sha-native.scm
- Removed unnecessary structs and unions from sha_context
- Used more efficient implementation of hex32
- Made (scheme base) a common import in (chibi crypto sha2)
This change concerns only Chibi. The portable implementation is
still kept around because it is... well... portable and can be
used by other Scheme implementations.
