This fixes .depend.genassym.o not being included. genassym.o depends on
all of the system headers and when rebuilt regenerates assym.s which
lists offsets for critial .S files to utilize. By having a struct in a
system header change its offsets and not have generassym.o be rebuilt,
this would lead to panics.
The flaw in the initial commit was seeing ${OBJS} in ${SYSTEM_OBJS} and
assuming it had all of ${SRCS} in it. This is not the case though. The
older mkdep code splits out all of the various SRC lists for generating
the .depend file. It also includes ${GEN_CFILES}, which had genassym.c
and was the only significant file lacking from ${SYSTEM_OBJS} upon inspection,
since it is not linked in. Rather than duplicate the likely
soon-to-be-removed mkdep lists, just add genassym.o to the DEPENDOBJS
list. Using ${SRCS} as bsd.dep.mk does would be nice but there are many
files in the build that are only added to ${OBJS} and not ${SRCS}, such
as bf_enc.o derived from bf_enc.S for i386.
Sponsored by: EMC / Isilon Storage Division
Reported by: dhw (several panics on current@)
Pointyhat to: bdrewery
dd076b9354