Mountain lion (clang 4.0) compatibility issue

[fsouza]

% ./configure --enable-clang
configure: looking for configure programs
configure: found cmp
configure: found mkdir
configure: found printf
configure: found cut
configure: found grep
configure: found xargs
configure: found cp
configure: found find
configure: found uname
configure: found date
configure: found tr
configure: found sed
configure: inspecting environment
configure: recreating config.tmp
configure: 
configure: processing /Users/f/Projects/rust/configure args
configure: 
configure: CFG_ENABLE_CLANG     := 1 
configure: CFG_PREFIX           := /usr/local 
configure: CFG_LOCAL_RUST_ROOT  := /usr/local 
configure: CFG_LLVM_ROOT        :=  
configure: CFG_HOST_TRIPLE      := x86_64-apple-darwin 
configure: CFG_TARGET_TRIPLES   := x86_64-apple-darwin 
configure: 
configure: looking for build programs
configure: 
configure: CFG_PERL             := /usr/bin/perl 
configure: CFG_CURL             := /usr/bin/curl (curl 7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8r zlib/1.2.5)
configure: CFG_PYTHON           := /usr/bin/python2.7 
configure: CFG_GIT              := /usr/local/bin/git (git version 1.7.11.3)
configure: CFG_CLANG            := /usr/bin/clang++ (Apple clang version 4.0 (tags/Apple/clang-421.0.57) (based on LLVM 3.1svn))
configure: CFG_GCC              := /usr/bin/gcc (i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00))
configure: CFG_LD               := /usr/bin/ld 
configure: CFG_LLVM_CONFIG      :=  
configure: CFG_VALGRIND         :=  
configure: CFG_PERF             :=  
configure: CFG_ISCC             :=  
configure: CFG_LLNEXTGEN        :=  
configure: CFG_PANDOC           :=  
configure: CFG_PDFLATEX         :=  
configure: CFG_XETEX            :=  
configure: CFG_LUATEX           :=  
configure: CFG_NODE             :=  
configure: error: bad CLANG version: 4.0, need >=3.0svn