perl 5.8.7: Fix the perl shared library generation for sh3/sh4

perl 5.8.7: Fix the perl shared library generation for sh3/sh4
targets:
- You cannot link using LD on sh3/sh4, since ld fails to link in the
  hidden library of weak symbols that is needed. Ccc knows about this
  library and correctly links it in. The generate_config_sh script
  was replacing the configred linker with LD from the environment and
  the soname patch was passing parameters directly to LD which need
  to be passed differently when linking with gcc.
- Any code to go in shared libraries must be compiled with -fPIC,
  which while present in the config file was again being replaced
  from the environment by the generate_config_sh script.
Both these patches probably should be ok for all targets, but they
would definately need run-time testing. So they are just patched in
for sh3 and sh4 for now.
Also removed the old code I added not to install the shared library
if its not configured since its configured for all targets after this
change.