msmtp: add optional libidn dependency

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/msmtp/msmtp.mk

@@ -8,9 +8,7 @@ MSMTP_VERSION = 1.6.6
 MSMTP_SITE = http://downloads.sourceforge.net/project/msmtp/msmtp/$(MSMTP_VERSION)
 MSMTP_SOURCE = msmtp-$(MSMTP_VERSION).tar.xz
 MSMTP_DEPENDENCIES = host-pkgconf
-MSMTP_CONF_OPTS = \
-	--without-libidn \
-	--disable-gai-idn
+MSMTP_CONF_OPTS = --disable-gai-idn
 MSMTP_LICENSE = GPL-3.0+
 MSMTP_LICENSE_FILES = COPYING
 
@@ -21,6 +19,13 @@ else
 MSMTP_CONF_OPTS += --without-libgsasl
 endif
 
+ifeq ($(BR2_PACKAGE_LIBIDN),y)
+MSMTP_CONF_OPTS += --with-libidn
+MSMTP_DEPENDENCIES += libidn
+else
+MSMTP_CONF_OPTS += --without-libidn
+endif
+
 ifeq ($(BR2_PACKAGE_LIBSECRET),y)
 MSMTP_CONF_OPTS += --with-libsecret
 MSMTP_DEPENDENCIES += libsecret