sysutils/sleuthkit: why CONFIGURE_STYLE=simple?

I just ran into this...

===> Configuring for sleuthkit-4.3.0p0
checking for a BSD-compatible install... /usr/obj/ports/sleuthkit-4.3.0/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/local/bin/gmkdir -p
[..snip..]
Making install in auto
/usr/local/bin/gmkdir -p '/usr/obj/ports/sleuthkit-4.3.0/fake-i386/usr/local/lib'
/bin/sh: /usr/local/bin/gmkdir: not found

...which shows that it's not using CONFIGURE_STYLE=gnu.

Is there a reason why?