ld-specific flags. LDFLAGS is really for ld-related flags for cc,
not for ld, and some flags, e.g., -Bshareable, mean completely
different things to cc and ld. Having the wrong things in LDFLAGS
also broke the standard ${PROG} target. This was kludged around
by using a special rule that depended on LDFLAGS being bogus.
Fixing `make depend' broke the special rule but fixed the standard
rule (except in the DESTDIR case, which was handled more strictly
here than elsewhere).