using libltdl from 2.2.x requires libtool 2.2.x to link against

[Steven Wu]

Per Ralf Wildenhues from libtool team. It seems that libtool generated  
from autogen.sh is incorrect for both 1.8.4 and 1.9.0 if using 2.2.x  
libltdl. The result will be a linking error "symbol  
_lt__PROGRAM__LTX_preloaded_symbols not found."

Even copy 2.2.x libtool, it is still wrong, since the _PROGRAM_   
should be "guile"

steve