How to build the shared library:

On x86/linux:

    cc -c intr.c
    ld -shared -o intr.so intr.o

On x86/MacOSX:

    cc -c intr.c
    libtool -dynamic -lSystemStubs -o intr.so intr.o -lc

On x86/Windows:

    cl /LD intr.c

    Note that you will also need to add extern __declspec(dllexport) to the
    function f() for it to be visible external to the DLL created.
    You will also need to update libh.sml to reference the DLL instead of the
    .so file.

On sparc/solaris:

    cc -c intr.c
    ld -G -o intr.so intr.o
