Index: head/lib/libsysdecode/Makefile
===================================================================
--- head/lib/libsysdecode/Makefile
+++ head/lib/libsysdecode/Makefile
@@ -107,7 +107,7 @@
 	sysdecode_mask.3 sysdecode_wait4_options.3 \
 	sysdecode_mask.3 sysdecode_wait6_options.3
 
-CLEANFILES= ioctl.c tables.h
+CLEANFILES= ioctl.c ioctl.c.tmp tables.h tables.h.tmp
 
 .if defined(COMPAT_32BIT)
 CPP+=	-m32
@@ -124,7 +124,8 @@
 
 DEPENDOBJS+=	tables.h
 tables.h: mktables
-	sh ${.CURDIR}/mktables ${SYSROOT:U${DESTDIR}}${INCLUDEDIR} ${.TARGET}
+	sh ${.CURDIR}/mktables ${SYSROOT:U${DESTDIR}}${INCLUDEDIR} ${.TARGET}.tmp && \
+	    mv -f ${.TARGET}.tmp ${.TARGET}
 
 # mkioctls runs find(1) for headers so needs to rebuild every time.  This used
 # to be a hack only done in buildworld.
Index: head/lib/libsysdecode/mktables
===================================================================
--- head/lib/libsysdecode/mktables
+++ head/lib/libsysdecode/mktables
@@ -123,7 +123,7 @@
 gen_table "rusage"          "RUSAGE_[A-Z]+[[:space:]]+[-0-9]+"             "sys/resource.h"
 gen_table "schedpolicy"     "SCHED_[A-Z]+[[:space:]]+[0-9]+"               "sched.h"
 gen_table "sendfileflags"   "SF_[A-Z]+[[:space:]]+[0-9]+"                  "sys/socket.h"
-gen_table "shmatflags"      "SHM_[A-Z]+[[:space:]]+[0-9]{6}+"              "sys/shm.h"
+gen_table "shmatflags"      "SHM_[A-Z]+[[:space:]]+[0-9]{6}"               "sys/shm.h"
 gen_table "shutdownhow"     "SHUT_[A-Z]+[[:space:]]+[0-9]+"                "sys/socket.h"
 gen_table "sigbuscode"      "BUS_[A-Z]+[[:space:]]+[0-9]+"                 "sys/signal.h"
 gen_table "sigchldcode"     "CLD_[A-Z]+[[:space:]]+[0-9]+"                 "sys/signal.h"