sd8516/                  project root
    runtime/
      crt0.sda             startup stub -- CALL main
      librt/               runtime functions
        divhi3.c
        modhi3.c
        divsi3.c
        muldi3.c
        ...
        softfloat/         the SF/DF families
      include/             freestanding headers (mine & what clang supplies)
      tests/               tests with checks

• Helper scripts were created this time: c2sda, c2ll, ll2sda and runtests.
• Next I had to modify VC-4 to take .sda files at the command line (to speed the dev cycle).
• Next I created the above directory.
• I will have to modify vc4 to look in ~/.vc4 if the files it needs are not in the pwd.