Update the DSO docs in the INSTALL file.

        To provide maximum flexibility Apache now is able to load

        modules under runtime via the DSO mechanism by using the

        pragmatic dlopen()/dlsym() system calls. These system calls

        pragmatic apr_dso_open()/apr_dso_sym() calls. These calls

        are not available under all operating systems therefore you

        cannot use the DSO mechanism on all platforms. And Apache

        currently has only limited built-in knowledge on how to

        compile shared objects because this is heavily

        platform-dependent. The current state is this:

        o Out-of-the-box supported platforms are (Not all of these

          will work currently.  DSO support is currently available on

          most of these platforms however):

           - Linux     - SunOS         - UnixWare     - Darwin/Mac OS

           - FreeBSD   - Solaris       - AIX          - OpenStep/Mach

           - OpenBSD   - IRIX          - SCO          - DYNIX/ptx

           - NetBSD    - HPUX          - ReliantUNIX

           - BSDI      - Digital Unix  - DGUX

        o Entirely unsupported platforms are:

           - Ultrix

        cannot use the DSO mechanism on all platforms. Apache relies

        on autoconf to detect the ability to use DSOs, and libtool to

        determine how to build DSOs. If your platform is supported by

        libtool, and we can find DSO system calls, then DSOs should

        work out-of-the-box. 

        If your system is not on these lists but has the dlopen-style

        interface, you either have to provide the appropriate compiler