"Unused function" build failure(s) — clang 3.6.0

-Wall -Werror are including the option -Wunused-function. Without not the case with g++
namespace { 
   void dummy_for_semicolon_do_not_use();
}
PackageVersionSupposed error messageFull log Bug report
cdebootstrap 0.6.4../../../../src/frontend/standalone/message.c:76:12: error: unused function 'unused' [-Werror,-Wunused-function] Log 751630
diskscan 0.14.1-6src/cdb.c:35:20: error: unused function 'set_uint64' [-Werror,-Wunused-function] Log
libcerf 1.3-2w_of_z.c:79:21: error: unused function 'cpolar' [-Werror,-Wunused-function] Log
roger-router 1.8.9-2gtk.c:46:1: error: unused function 'routermanager_statusicon_plugin_get_instance_private' [-Werror,-Wunused-function] Log
xorp 1.8.5-4libxipc/xrl_parser.cc:112:1: error: unused function 'advance_to_either' [-Werror,-Wunused-function] Log

5 errors