Shared Images:
-------------
  Solaris:
    > gcc -fPIC -c mycode.c
        Note: according to National Instruments web page, gcc does
        not link position-independent code correctly.  That's why
        we do the compile and link in two steps.  The web page is
        pretty old (1999?), so this may no longer be true.
    > ld -G -o mycode.so mycode.o
           \
            make shared image

    However, the *same* web page gives these alternatives for
    "one step" compilation and linking:
    > gcc -fPIC -G -o mycode.so mycode.c
       or
    > gcc -fPIC -share -fno-gnu-linker -o mycode.so mycode.c

Link flags:
----------
  o alpha-Linux:  SHAREFLAGS = -G
  o i686-Linux:   SHAREFLAGS = -shared
  o sun4u-SunOS:  SHAREFLAGS = -G -Bsymbolic