* libltdl/configure.in (libltdl_cv_shlibext, LTDL_SHLIB_EXT):

	* libltdl/configure.in (libltdl_cv_shlibext, LTDL_SHLIB_EXT):
	system-dependent extension of shared libraries
	(libltdl_cv_shlibpath_var, LTDL_SHLIBPATH_VAR): system-dependent
	run-time shared library search path
	* libltdl/ltdl.c (dldpre_init, dldpre_exit): unrelate init/exit
	from add/remove symlists, so one may add dld_preloaded_symbols
	from main(), when only a library will call dldpre_init
	(lt_dlopen): use LTDL_SHLIBPATH_VAR, if defined, as secondary
	search path.  Also, if a requested .la file cannot be found, try
	with the LTDL_SHLIB_EXTension instead.