import from branch_1_1:

import from branch_1_1:
	update libtool and libltdl to 1.5.22, and improve the integration
	by not requiring source modification (except for one change to
	ltdl.c [for a bug] to follow)

	Note that this reverses ltdl.c#1.8 but we will re-apply it.  The
	reason not to simply include it in this commit is so that all
	the files here serve as a baseline of unmodified libtool/libltdl
	sources, making it easier to update it in the future.