package/log4qt: link with latomic if needed

Fixes:
 - http://autobuild.buildroot.net/results/fb5/fb52f5366a25230606149f44dc46f86f0273a680/

Signed-off-by: Bartosz Bilas <b.bilas@grinn-global.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/log4qt/log4qt.mk

@@ -11,6 +11,11 @@ LOG4QT_LICENSE = Apache-2.0
 LOG4QT_LICENSE_FILES = LICENSE
 LOG4QT_INSTALL_STAGING = YES
 
+# Uses __atomic_fetch_add_4
+ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
+LOG4QT_CONF_OPTS += -DCMAKE_EXE_LINKER_FLAGS=-latomic
+endif
+
 ifeq ($(BR2_PACKAGE_QT5BASE_SQLITE_QT)$(BR2_PACKAGE_QT5BASE_SQLITE_SYSTEM),y)
 LOG4QT_CONF_OPTS += -DBUILD_WITH_DB_LOGGING=ON
 else