package/screen: add linux-pam optional dependency

linux-pam is an optional dependency for more than 5 years:
https://git.savannah.gnu.org/cgit/screen.git/commit/src/configure.ac?h=screen-v4&id=a8dc1fb5b47ee52c79884fc5270805a3a39cda4a

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/screen/screen.mk

@@ -14,6 +14,13 @@ SCREEN_CONF_ENV = CFLAGS="$(TARGET_CFLAGS)"
 SCREEN_CONF_OPTS = --enable-colors256
 SCREEN_INSTALL_TARGET_OPTS = DESTDIR=$(TARGET_DIR) SCREEN=screen install_bin
 
+ifeq ($(BR2_PACKAGE_LINUX_PAM),y)
+SCREEN_DEPENDENCIES += linux-pam
+SCREEN_CONF_OPTS += --enable-pam
+else
+SCREEN_CONF_OPTS += --disable-pam
+endif
+
 define SCREEN_INSTALL_SCREENRC
 	$(INSTALL) -m 0755 -D $(@D)/etc/screenrc $(TARGET_DIR)/etc/screenrc
 endef