libmicrohttpd: fix static linking with gnutls

Fixes http://autobuild.buildroot.net/results/f5a/f5a135647867ca98ce6189bb343a631ce6a47e23/

gnutls links to a number of libraries depending on configuration (pthread,
iconv, ..), so we need to link against those as well when statically
linking.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libmicrohttpd/libmicrohttpd.mk

@@ -12,7 +12,8 @@ LIBMICROHTTPD_CONF_OPTS = --disable-curl --disable-spdy
 
 ifeq ($(BR2_PACKAGE_LIBMICROHTTPD_SSL),y)
 LIBMICROHTTPD_LICENSE = LGPLv2.1+
-LIBMICROHTTPD_DEPENDENCIES += gnutls libgcrypt
+LIBMICROHTTPD_DEPENDENCIES += host-pkgconf gnutls libgcrypt
+LIBMICROHTTPD_CONF_ENV += LIBS="$(shell $(PKG_CONFIG_HOST_BINARY) --libs gnutls)"
 LIBMICROHTTPD_CONF_OPTS += --enable-https --with-gnutls=$(STAGING_DIR)/usr \
 	--with-libgcrypt-prefix=$(STAGING_DIR)/usr
 else