This may be amiga-specific.

0:T:/usr/src/sys/arch/amiga/stand/loadkmap/din
$ make install
install -c -s -o bin -g bin  -m 555 din-kbdmap /mnt/mnt/usr/share/keymaps/amiga/din-kbdmap
install: /mnt/mnt/usr/share/keymaps/amiga/din-kbdmap: No such file or directory
*** Error code 1

Stop.

This is done with DESTDIR=/mnt.  No other install seems to fail.  My
workaround was to mkdir /mnt/mnt, and ln -s /mnt/usr /mnt/mnt/usr, but
this is hardly correct.  It works fine without a DESTDIR.

(I'm building a new bootable system from my primary -amiga system,
so I want this to work.)

-s