diff --git a/sys/conf/Makefile.alpha b/sys/conf/Makefile.alpha
index fff6a2461377..c447400a83b0 100644
--- a/sys/conf/Makefile.alpha
+++ b/sys/conf/Makefile.alpha
@@ -183,10 +183,10 @@ setdef0.c setdef1.c setdefs.h: Makefile ${OBJS}
 ./assym.s: assym.s
 
 assym.s: $S/kern/genassym.sh genassym.o
-	sh $S/kern/genassym.sh genassym.o > ${.TARGET}
+	OBJFORMAT=elf sh $S/kern/genassym.sh genassym.o > ${.TARGET}
 
 genassym.o: $S/$M/$M/genassym.c
-	${CC} -c ${CFLAGS} $S/$M/$M/genassym.c
+	${CC} -c ${CFLAGS} -elf $S/$M/$M/genassym.c
 
 SYSTEM_OBJS+=	__divqu.o __divq.o __divlu.o __divl.o
 SYSTEM_OBJS+=	__remqu.o __remq.o __remlu.o __reml.o
diff --git a/sys/conf/Makefile.i386 b/sys/conf/Makefile.i386
index f92c6543e43b..d42199ca8adc 100644
--- a/sys/conf/Makefile.i386
+++ b/sys/conf/Makefile.i386
@@ -188,10 +188,10 @@ setdef0.c setdef1.c setdefs.h: Makefile ${OBJS}
 ./assym.s: assym.s
 
 assym.s: $S/kern/genassym.sh genassym.o
-	sh $S/kern/genassym.sh genassym.o > ${.TARGET}
+	OBJFORMAT=elf sh $S/kern/genassym.sh genassym.o > ${.TARGET}
 
 genassym.o: $S/$M/$M/genassym.c
-	${CC} -c ${CFLAGS} $S/$M/$M/genassym.c
+	${CC} -c ${CFLAGS} -elf $S/$M/$M/genassym.c
 
 ${SYSTEM_OBJS} genassym.o vers.o: opt_global.h
 
diff --git a/sys/conf/Makefile.pc98 b/sys/conf/Makefile.pc98
index 93326557426c..9bafc06ad76a 100644
--- a/sys/conf/Makefile.pc98
+++ b/sys/conf/Makefile.pc98
@@ -190,11 +190,11 @@ setdef0.c setdef1.c setdefs.h: Makefile ${OBJS}
 ./assym.s: assym.s
 
 assym.s: $S/kern/genassym.sh genassym.o
-	sh $S/kern/genassym.sh genassym.o > ${.TARGET}
+	OBJFORMAT=elf sh $S/kern/genassym.sh genassym.o > ${.TARGET}
 
 genassym.o: $S/$M/$M/genassym.c
 	rm -f ./machine ; ln -s $S/$M/include ./machine
-	${CC} -c ${CFLAGS} $S/$M/$M/genassym.c
+	${CC} -c ${CFLAGS} -elf $S/$M/$M/genassym.c
 
 ${SYSTEM_OBJS} genassym.o vers.o: opt_global.h
 
diff --git a/sys/conf/Makefile.powerpc b/sys/conf/Makefile.powerpc
index f92c6543e43b..d42199ca8adc 100644
--- a/sys/conf/Makefile.powerpc
+++ b/sys/conf/Makefile.powerpc
@@ -188,10 +188,10 @@ setdef0.c setdef1.c setdefs.h: Makefile ${OBJS}
 ./assym.s: assym.s
 
 assym.s: $S/kern/genassym.sh genassym.o
-	sh $S/kern/genassym.sh genassym.o > ${.TARGET}
+	OBJFORMAT=elf sh $S/kern/genassym.sh genassym.o > ${.TARGET}
 
 genassym.o: $S/$M/$M/genassym.c
-	${CC} -c ${CFLAGS} $S/$M/$M/genassym.c
+	${CC} -c ${CFLAGS} -elf $S/$M/$M/genassym.c
 
 ${SYSTEM_OBJS} genassym.o vers.o: opt_global.h