package/dfu-programmer: link with -latomic if needed

Fixes:
http://autobuild.buildroot.net/results/e2b/e2b813fdcbb3862366609affe88551c3036b21b8/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/dfu-programmer/dfu-programmer.mk

@@ -18,4 +18,8 @@ endef
 
 DFU_PROGRAMMER_POST_PATCH_HOOKS == DFU_PROGRAMMER_ADD_MISSING_FILE
 
+ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
+DFU_PROGRAMMER_CONF_OPTS += LIBS=-latomic
+endif
+
 $(eval $(autotools-package))