depend-cleanup.sh: Generalise lib32 code and avoid duplication
    
    By passing through _ALL_libcompats we can avoid hard-coding the list of
    libcompats in depend-cleanup.sh. This cleanup also makes clean_dep
    shorter by using a loop instead of handling each case explicitly (at the
    expense of slightly tweaked logging).
    
    Reviewed by:	brooks, jhb
    Differential Revision:	https://reviews.freebsd.org/D41187
    
    (cherry picked from commit 81805ec30074363e5d7d7add37b3ccf4f1eb396b)
    
    Pull Request:	https://github.com/freebsd/freebsd-src/pull/1543