Clang Linkerflags.

script/ci_build.sh

@@ -3,12 +3,13 @@
 set -ex
 
 if [[ "${CXX}" == clang* ]]; then
-    export CXXFLAGS="-stdlib=libc++ -lc++abi"
+    export CXXFLAGS="-stdlib=libc++"
+    EXTRA="-DCMAKE_EXE_LINKER_FLAGS=-lc++abi -lc++"
 fi
 
 mkdir build && cd build
 
-cmake ..
+cmake ${EXTRA} ..
 make
 make unittest