so CFLAGS is used as set in the standard make(1) rules of the platform.
This should fix the problem that "-pipe" is not available on IRIX.
Don't use mv(1) or rm(1) when installing -- the binary should not be
there anyway when using pkgsrc.
Don't define ${INSTALL} -- it should be pointing to the BSD install(1)
already in the standard make(1) rules of the platform (or somehow
inherited from pkgsrc rules). Works for NetBSD, untested elsewhere.
Based on suggestions in PR pkg/27429 by Georg Schwarz.