When I build llvm using llvm/clang as opposed to gcc I get the following: configure:2921: $? = 0 configure:2928: /home/rkotler/myclang/bin/clang++ -V >&5 clang: error: argument to '-V' is missing (expected 1 value) clang: error: no input files configure:2931: $? = 1 configure:2934: checking whether we are using the GNU C++ compiler