Hi, to enable use of clang++ with the new libc++ (or to explicitely select the GNU libstdc++) libtool should accept and pass the linker flag "-stdlib=*" Attached is the patch and - as required on the web site + README - the output of make -k check. The tests were run on OSX 10.7 with llvm-gcc 4.2 I tested the patch itself by building cppunit with CXXFLAGS and LDFLAGS set to "-stdlib=libc++". Regards Titus