"Argument unused caused failure" build failure(s) — clang 3.4.2

Unknown or unused arguments triggers errors with -Werror:
clang -Werror -ggdb3 foo.c
PackageVersionSupposed error messageFull log Bug report
dwb 20140415hg-1clang: error: argument unused during compilation: '--ansi' Log
lebiniou 3.20-1clang: error: argument unused during compilation: '-e xport-dynamic' Log
libwebsockets 1.2.2-1clang: error: argument unused during compilation: '-rdynamic' Log
lxc 1.0.4-3clang: error: argument unused during compilation: '-L../../src/lxc/' Log
policycoreutils 2.3-1clang: error: argument unused during compilation: '-shared' Log

5 errors