package/linux-pam: adjust login pam file for lastlog

when pam_lastlog.so is not installed login issues an error
that it is not able to load it.

Hence only enable the entry when pam_lastlog.so is installed.

Fixes:
 login[649]: PAM unable to dlopen(/lib/security/pam_lastlog.so): /lib/security/pam_lastlog.so: cannot open shared object file: No such file or directory
 login[649]: PAM adding faulty module: /lib/security/pam_lastlog.so

Signed-off-by: Michael Nosthoff <buildroot@heine.tech>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit ee5c08aa88757c214172161b469437450880a7f8)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/linux-pam/linux-pam.mk

@@ -56,6 +56,10 @@ endif
 
 ifeq ($(BR2_PACKAGE_LINUX_PAM_LASTLOG),y)
 LINUX_PAM_CONF_OPTS += --enable-lastlog
+define LINUX_PAM_LASTLOG_PAMFILE_TWEAK
+	$(SED) 's/^# \(.*pam_lastlog.so.*\)$$/\1/' \
+		$(TARGET_DIR)/etc/pam.d/login
+endef
 else
 LINUX_PAM_CONF_OPTS += --disable-lastlog
 endif
@@ -66,6 +70,7 @@ define LINUX_PAM_INSTALL_CONFIG
 		$(TARGET_DIR)/etc/pam.d/login
 	$(INSTALL) -m 0644 -D package/linux-pam/other.pam \
 		$(TARGET_DIR)/etc/pam.d/other
+	$(LINUX_PAM_LASTLOG_PAMFILE_TWEAK)
 	$(LINUX_PAM_SELINUX_PAMFILE_TWEAK)
 endef
 

package/linux-pam/login.pam

@@ -8,5 +8,5 @@ password	required	pam_unix.so nullok
 session		required	pam_limits.so
 session		required	pam_env.so
 session		required	pam_unix.so
-session		optional	pam_lastlog.so
+# session	optional	pam_lastlog.so
 # session	required	pam_selinux.so open