Set GNU_CONFIGURE since this port uses it
Don't use an internal libtool, use the system one. Port build is still
broken on -current because of expr(1) abuse in the libtool port.
hanemacs and hmconv had invalid version strings (fixed).
I also got replaced AMI_VER and HANIM_VER with PORTVERSION but I
didn't touch BROWSER_VER (in netscape ports) since it was used in too
many places.