perl5 has a working model of this that you may want to use.
   See perl5.000/ext/DynaLoader/dl_dlopen.xs.

relatively working.  you build Tk.so with -lX11 where the X11
library is also a shared library, it will fail.  actually, the
tk perl extension never works as a shared object, but you get
the same problem with the curses library (which links with the
curses shared library).