hardcoded -C argument to ${INSTALL}

Hi,

I'm putting a script together that will remove stale pieces after an 
installworld, and my find+mtime approach chokes, because some uses of 
${INSTALL} in the Makefiles hardcode the -C argument, which will cause 
file modification times to not be updated if the files are identical.

For example:
	include/Makefile
	share/mk/bsd.incs.mk
	sys/boot/efi/loader/Makefile
	sys/boot/alpha/common/Makefile.common
	...

I'm no guru on the buildworld process, so I'm wondering whether this is 
by design, or an oversight? Can the -C be removed without ill effects?

If so, I'd be happy to take post a patch; let me know.

Thanks,
Lars
-- 
Lars Eggert <larse_at_isi.edu>           USC Information Sciences Institute