diff --git a/usr.sbin/acpi/acpidb/Makefile b/usr.sbin/acpi/acpidb/Makefile
index e8c98a6b4eb1..288f86ea3756 100644
--- a/usr.sbin/acpi/acpidb/Makefile
+++ b/usr.sbin/acpi/acpidb/Makefile
@@ -2,7 +2,7 @@
 
 PROG=	acpidb
 SRCS+=	acpidb.c
-SRCS+=	osunixxf.c
+SRCS+=	osunixxf-xxx.c
 SRCS+=	dbcmds.c dbdisply.c dbexec.c dbfileio.c \
 	dbhistry.c dbinput.c dbstats.c dbutils.c \
 	dbxface.c dmbuffer.c dmnames.c dmobject.c \
@@ -39,4 +39,8 @@ MAN=	acpidb.8
 CFLAGS+= -DACPI_APPLICATION -DACPI_DEBUG_OUTPUT -DACPI_DEBUGGER \
 	-DACPI_DISASSEMBLER
 
+CLEANFILES+= osunixxf-xxx.c
+osunixxf-xxx.c: osunixxf.c
+	cat ${.ALLSRC} | sed -e 's/UINT32 *length/ACPI_SIZE length/g' -e 's/UINT32 *size/ACPI_SIZE size/g' -e 's/(UINT32) where/(uintptr_t)where/g' > ${.TARGET}
+
 .include <bsd.prog.mk>