optional_depends pcre \
                 "--enable-pcre" \
                 "--with-pcrebuild" \
                 "to use system PCRE library" &&

if [[ $RSERV_DBB == postgresql ]]; then
  depends postgresql '--enable-pgsql'
elif [[ $RSERV_DBB == mysql ]]; then
  depends MYSQL '--enable-mysql'
else
  optional_depends sqlite \
                   "--enable-sqlite3" \
                   "--with-sqlitebuild" \
                   "to use system SQLite library"
fi

.