According to comments in the Makefile, to make pxeboot work (is this still true,
and if so why?) we need to have crt0.o first. We've done this by adding it to
OBJS before all the other .o's are added. However, there's a problem. This also
adds it to the CLEANFILES variable, which causes it to be removed from multiple
places. The dependencies may also cause it to be re-built at a time that's after
boot2 is built. This causes installs to fail because at install time boot2 is
considered to be out of date and the programs to rebuild it are no longer in the
Cope with this problem by just adding it to LDFLAGS instead.