• respect PREFIX for location of uhidd.conf
• use PTHREAD_LIBS instead of -lpthread
• try to guess kernel sources based on SYSDIR (used by bsd.kmod.mk) or SRC_BASE (used by ports like virtualbox and kqemu)
• use KMODDIR in plist, too
• I don't think SUB_FILES needs to be *after* bsd.port.pre.mk
• inherit DEBUG_FLAGS from make.conf, not only from command line
• mimic bsd.kmod.mk in installing .symbols file and add entry to plist

PR: ports/147898
Submitted by: Anonymous <swell.k@gmail.com>
Approved by: Kai Wang <kaiwang27@gmail.com> (maintainer)