shadow should allow to have passwd files on /data partition

Makefile

@@ -18,3 +18,16 @@ all:
 	pwconv
 	grpconv
 	rm -rf shadow-4.6
+
+data:
+	tar xf shadow-4.6.tar.xz
+	patch -Np1 -d shadow-4.6 < shadow-4.6-allowsymlinks.patch
+	cd shadow-4.6 && sed -i 's/groups$(EXEEXT) //' src/Makefile.in
+	cd shadow-4.6 && find man -name Makefile.in -exec sed -i -e 's/groups\.1 / /' -e 's/getspnam\.3 / /' -e 's/passwd\.5 / /' '{}' \;
+	cd shadow-4.6 && sed -i -e 's@#ENCRYPT_METHOD DES@ENCRYPT_METHOD SHA512@' -e 's@/var/spool/mail@/var/mail@' etc/login.defs
+	cd shadow-4.6 && sed -i 's/1000/999/' etc/useradd
+	cd shadow-4.6 && ./configure --sysconfdir=/etc --with-group-name-max-length=32
+	$(MAKE) -C shadow-4.6
+	$(MAKE) -C shadow-4.6 install
+	mv -vf /usr/bin/passwd /bin
+	rm -rf shadow-4.6

shadow-4.6-allowsymlinks.patch

+diff -uNr shadow-4.6/lib/commonio.c shadow-4.6-allowsymlinks/lib/commonio.c
+--- shadow-4.6/lib/commonio.c	2018-04-30 02:12:37.000000000 +0930
++++ shadow-4.6-allowsymlinks/lib/commonio.c	2019-03-23 20:40:51.378977190 +1030
+@@ -632,7 +632,7 @@
+ 
+ 	fd = open (db->filename,
+ 	             (db->readonly ? O_RDONLY : O_RDWR)
+-	           | O_NOCTTY | O_NONBLOCK | O_NOFOLLOW);
++	           | O_NOCTTY | O_NONBLOCK);
+ 	saved_errno = errno;
+ 	db->fp = NULL;
+ 	if (fd >= 0) {