* libltdl/m4/libtool.m4 (_LT_PROG_XSI_SHELLFNS): Move non-XSI

* libltdl/m4/libtool.m4 (_LT_PROG_XSI_SHELLFNS): Move non-XSI
definition of func_dirname_and_basename ...
* libltdl/config/general.m4sh (func_dirname_and_basename):
... here, to use it for the other scripts that use general.m4sh
(and as portable fallback for libtool).  Add marker for early
insertion of generated shell functions (into libtool, not the
other scripts) here.
Use func_dirname_and_basename to compute progname, progpath.
* libltdl/config/ltmain.m4sh (func_mode_help): Remove marker
for insertion of generated shell functions.
* tests/sh.test: Adjust function definition test to not match
function call.