optional_depends popt \
                 "--without-included-popt" \
                 "--with-included-popt" \
                 "to use system popt library instead of bundled" &&

optional_depends acl \
                 "--enable-acl-support" \
                 "--disable-acl-support" \
                 "for ACL support" &&

optional_depends attr \
                 "--enable-xattr-support" \
                 "--disable-xattr-support" \
                 "for extended attributes support"