I pulled down current (on a 1.2.1 base) and started a build
of the kernel.  I get:
cc -x assembler-with-cpp -traditional-cpp -D_LOCORE -I. -I../../../../arch -I../../../.. -nostdinc -DSWAPPAGER -DVNODEPAGER -DDEVPAGER -DEXEC_AOUT -DEXEC_SCRIPT -DI386_CPU -DI486_CPU -DI586_CPU -DI686_CPU -DMATH_EMULATE -DBIOSEXTMEM="0x1fc00" -DDUMMY_NOPS -DXSERVER -DUCONSOLE -DINSECURE -DRTC_OFFSET="0" -DDDB -DDIAGNOSTIC -DKTRACE -DSYSVMSG -DSYSVSEM -DSYSVSHM -DCOMPAT_NOMID -DCOMPAT_09 -DCOMPAT_10 -DCOMPAT_11 -DCOMPAT_12 -DCOMPAT_43 -DTCP_COMPAT_42 -DCOMPAT_SVR4 -DCOMPAT_IBCS2 -DCOMPAT_LINUX -DCOMPAT_FREEBSD -DEXEC_ELF32 -DUSER_LDT -DLKM -DFFS -DLFS -DMFS -DNFS -DCD9660 -DMSDOSFS -DFDESC -DKERNFS -DNULLFS -DPORTAL -DPROCFS -DUMAPFS -DUNION -DQUOTA -DNFSSERVER -DFIFO -DGATEWAY -DINET -DNS -DPFIL_HOOKS -DISO -DTPIP -DEON -DCCITT -DLLC -DHDLC -DEISAVERBOSE -DPCIVERBOSE -DMAXUSERS=32 -D_KERNEL  -Di386 -c ../../../../arch/i386/i386/locore.s
../../../../arch/i386/i386/locore.s: Assembler messages:
../../../../arch/i386/i386/locore.s:133: Error: Unknown expression
../../../../arch/i386/i386/locore.s:134: Error: Unknown expression
../../../../arch/i386/i386/locore.s:135: Error: Unknown expression
../../../../arch/i386/i386/locore.s:136: Error: Unknown expression
../../../../arch/i386/i386/locore.s:143: Error: Unknown expression
../../../../arch/i386/i386/locore.s:144: Error: Unknown expression
../../../../arch/i386/i386/locore.s:145: Error: Unknown expression
../../../../arch/i386/i386/locore.s:522: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/i386/locore.s:537: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/i386/locore.s:574: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/i386/locore.s:1997: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:221: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:222: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:223: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:224: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:225: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:226: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:227: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:228: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:229: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:230: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:231: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:232: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:233: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:234: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:235: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/isa/vector.s:236: Error: Unimplemented segment type 0 in parse_operand
../../../../arch/i386/i386/locore.s:2269: Error: Unimplemented segment type 0 in parse_operand

Any ideas on what I need to play with to get this to compile correctly?

TIA,
Paul