Just got a more interesting compile error along the same vein as the
dhcp one:

cc -O  -Werror -Wall -Wstrict-prototypes -Wmissing-prototypes
  -Wpointer-arith  -c /usr/src/usr.sbin/sa/main.c
/usr/src/usr.sbin/sa/main.c: In function `acct_load':
/usr/src/usr.sbin/sa/main.c:363: internal error--unrecognizable insn:
(insn 171 167 173 (set (reg:QI 61)
        (mem/s:QI (plus:SI (reg:SI 59)
                (subreg:SI (reg:DI 135) 0)))) -1 (insn_list 167 (nil))
    (expr_list:REG_DEAD (reg:SI 59)
        (nil)))
cc: Internal compiler error: program cc1 got fatal signal 6
*** Error code 1

which also goes away with the -O.

Cheers,

Patrick