Commit a8a65c7f6c6b6463bbdee119c0ff71536925e455

✈ Graham ✈ 2017-09-26T13:27:52

Only add warnings and std flags if supported by compiler (autoconf) (#145) * Only add warning and std flags if supported by compiler (autoconf) * bundle AX_CHECK_COMPILE_FLAG macro from autoconf-archive