This commit fixes the run-libmicro command which was broken for all
platforms. It was pointing at the destdir version instead of the
installed version.
It also provides a DragonFly-specific makefile which enables it to
build and run on DragonFly.
LibMicro is a portable set of microbenchmarks that many Solaris engineers
used during Solaris 10 development to measure the performance of various
system and library calls. LibMicro was developed by Bart Smaalders and
Phil Harman as part of their "If Linux is faster it's a Solaris bug
performance" campaign.