libxml2-2.9.2 make error "./.libs/libxml2.so: undefined reference to `gzopen64'"

$ make
  :
make[2]: Entering directory `/home/endo/tmp/libxml2-2.9.2'
  CCLD     xmllint
./.libs/libxml2.so: undefined reference to `gzopen64'
collect2: ld returned 1 exit status
make[2]: *** [xmllint] Error 1
make[2]: Leaving directory `/home/endo/tmp/libxml2-2.9.2'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/endo/tmp/libxml2-2.9.2'
make: *** [all] Error 2
$

なんで?
https://forum.directadmin.com/showthread.php?t=43000
では、↑こちらの通り「--with-zlib=/usr/local」を追加して解決

$ configure --with-zlib=/usr/local
$ make
$