package/ecryptfs-utils: add optional dependency on linux-pam

If linux-pam is enabled, we want to build pam_ecryptfs.so and install
it into /lib/security/.

Signed-off-by: Yi Zheng <goodmenzy@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/ecryptfs-utils/ecryptfs-utils.mk

@@ -11,13 +11,20 @@ ECRYPTFS_UTILS_LICENSE = GPL-2.0+
 ECRYPTFS_UTILS_LICENSE_FILES = COPYING
 
 ECRYPTFS_UTILS_DEPENDENCIES = keyutils libnss host-intltool
-ECRYPTFS_UTILS_CONF_OPTS = --disable-pywrap --disable-pam
+ECRYPTFS_UTILS_CONF_OPTS = --disable-pywrap
 
 #Needed for build system to find pk11func.h and libnss3.so
 ECRYPTFS_UTILS_CONF_ENV = \
 	NSS_CFLAGS="-I$(STAGING_DIR)/usr/include/nss -I$(STAGING_DIR)/usr/include/nspr" \
 	NSS_LIBS="-lnss3"
 
+ifeq ($(BR2_PACKAGE_LINUX_PAM),y)
+ECRYPTFS_UTILS_CONF_OPTS += --enable-pam
+ECRYPTFS_UTILS_DEPENDENCIES += linux-pam
+else
+ECRYPTFS_UTILS_CONF_OPTS += --disable-pam
+endif
+
 ifeq ($(BR2_PACKAGE_OPENSSL),y)
 ECRYPTFS_UTILS_CONF_OPTS += --enable-openssl
 ECRYPTFS_UTILS_DEPENDENCIES += openssl