Index: Makefile.inc1
===================================================================
--- Makefile.inc1
+++ Makefile.inc1
@@ -712,6 +712,21 @@
 .else
 	rm -rf ${WORLDTMP}/legacy/usr/include
 .endif
+# Dependencies cannot cope with certain source tree changes, particularly
+# with respect to removing source files and replacing generated files.
+# Handle these cases here in an ad-hoc fashion.
+# 20170523 remove stale generated asm files for functions which are no longer
+# syscalls after r318736
+.if exists(${OBJTREE}${.CURDIR}/lib/libc/getdents.s) || \
+    exists(${OBJTREE}${.CURDIR}/lib/libc/getdents.S)
+	@echo removing stale generated syscall asm files
+.for f in getdents lstat mknod stat
+	@rm -f ${OBJTREE}${.CURDIR}/lib/libc/${f}.* \
+	@rm -f ${OBJTREE}${.CURDIR}/lib/libc/.depend.${f}.* \
+	@rm -f ${OBJTREE}${.CURDIR}/world32/${.CURDIR}/lib/libc/${f}.* \
+	@rm -f ${OBJTREE}${.CURDIR}/world32/${.CURDIR}/lib/libc/.depend.${f}.*
+.endfor
+.endif
 .for _dir in \
     lib lib/casper usr legacy/bin legacy/usr
 	mkdir -p ${WORLDTMP}/${_dir}