diff --git a/sys/conf/Makefile.powerpc b/sys/conf/Makefile.powerpc
index caa127b03c31..8e22e0496123 100644
--- a/sys/conf/Makefile.powerpc
+++ b/sys/conf/Makefile.powerpc
@@ -33,15 +33,10 @@ S=	../../..
 .endif
 .include "$S/conf/kern.pre.mk"
 
-_OS!=uname
-.if ${_OS} != "FreeBSD"
-CWARNFLAGS=-Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
-	   -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual
-COPTS+= -D__FreeBSD__
-.endif
-
 COPTS+= -msoft-float
 
+SYSTEM_SFILES= $S/$M/$M/locore.S
+
 %BEFORE_DEPEND
 
 %OBJS
@@ -54,7 +49,7 @@ COPTS+= -msoft-float
 
 %CLEAN
 
-locore.o: $S/$M/$M/locore.s assym.s
+locore.o: $S/$M/$M/locore.S assym.s
 	${NORMAL_S}
 
 %RULES