The port/pg_latch.c symlink ought to be removed by make distclean.

Not sure why these symlinks are removed here and not in the port/
Makefile, but I won't second-guess that choice right now.

src/backend/Makefile

@@ -281,7 +281,8 @@ ifeq ($(PORTNAME), win32)
 endif
 
 distclean: clean
-	rm -f port/tas.s port/dynloader.c port/pg_sema.c port/pg_shmem.c
+	rm -f port/tas.s port/dynloader.c port/pg_sema.c port/pg_shmem.c \
+	      port/pg_latch.c
 
 maintainer-clean: distclean
 	rm -f bootstrap/bootparse.c \