we're presented with...

CXX="/usr/local/bin/clang++"
CC="/usr/local/bin/clang"
CXXFLAGS="-g -stdlib=libc++"

and out of the box we fail to build, but if we reshuffle to...

CXX="/usr/local/bin/clang++ -stdlib=libc++"
CC="/usr/local/bin/clang -stdlib=libc++"
CXXFLAGS="-g"
LDFLAGS="-lpthread"

then with this distro-config we build to completion

Change-Id: Ib6bee4dd69e0609e3c1238d86837a1680483ffa4