ulogd: disable DB backends if no threads

Database backends need threads even if sqlite does not.
The mysql client libs need them too but include them in the exclusion
closure anyway to state it very clearly. Fixes:
http://autobuild.buildroot.net/results/1ce/1cece0db309dfe5cecc69e88b02428615ed87316/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/ulogd/ulogd.mk

@@ -11,15 +11,21 @@ ULOGD_CONF_OPT = --with-dbi=no --with-pgsql=no
 ULOGD_AUTORECONF = YES
 ULOGD_DEPENDENCIES = host-pkgconf \
 	libmnl libnetfilter_acct libnetfilter_conntrack libnetfilter_log \
-	libnfnetlink $(if $(BR2_PACKAGE_SQLITE),sqlite)
+	libnfnetlink
 ULOGD_LICENSE = GPLv2
 ULOGD_LICENSE_FILES = COPYING
 
+# DB backends need threads
+ifeq ($(BR2_TOOLCHAIN_HAS_THREADS),y)
 ifeq ($(BR2_PACKAGE_MYSQL_CLIENT),y)
-ULOGD_CONF_OPT += --with-mysql=$(STAGING_DIR)/usr
-ULOGD_DEPENDENCIES += mysql_client
+	ULOGD_CONF_OPT += --with-mysql=$(STAGING_DIR)/usr
+	ULOGD_DEPENDENCIES += mysql_client
+endif
+ifeq ($(BR2_PACKAGE_SQLITE),y)
+	ULOGD_DEPENDENCIES += sqlite
+endif
 else
-ULOGD_CONF_OPT += --with-mysql=no
+	ULOGD_CONF_OPT += --with-mysql=no --without-sqlite
 endif
 
 $(eval $(autotools-package))