fix #DEFINE ORADEFS in oradefs.h
rename oraconst.h to oradefs.h
Remove the RTLD_NODELETE flag from dlopen()
update oratypes.h
Use SHLIB_SUFFIX instead of hard coded value for shared lib suffix.
use DLOPEN for unix code
added some x-platform dlsym magic macros
add test for HAVE_DLFCN_H
SHLIB_SUFFIX moved later - must come after CONFIG_CFLAGS
added -DSHLIB_SUFFIX to DEFS
