Sometimes we observe:

    /usr/bin/ld: cannot find -laspell
    collect2: error: ld returned 1 exit status
    libtool: install: error: relink `email-filter.la' with the above command before installing it
    Makefile:960: recipe for target 'install-filterLTLIBRARIES' failed

/reviewed-on nexedi/slapos!652