Rename _LT_PROG_XSI_REPLACE macro to _LT_PROG_FUNCTION_REPLACE.

Rename _LT_PROG_XSI_REPLACE macro to _LT_PROG_FUNCTION_REPLACE.

* libltdl/m4/libtool.m4 (_LT_PROG_XSI_SHELLFNS): Rename to
_LT_PROG_REPLACE_SHELLFNS.
(_LT_PROG_XSI_REPLACE): Rename to _LT_PROG_FUNCTION_REPLACE.
(_LT_PROG_FUNCTION_REPLACE): Change decorator comment to use
'Extended shell' rather than 'XSI' on successful replacement.
* libltdl/config/general.m4sh (func_dirname, func_basename)
(func_dirname_and_basename, func_stripname): Change decorator
comment to use 'extended shell' rather than 'XSI' on fallback
implementations.
* libltdl/config/getopt.m4sh (func_split_short_opt)
(func_split_long_opt): Ditto.
* libltdl/config/ltmain.m4sh (func_append, func_append_quoted)
(func_arith, func_len, func_lo2o, func_xform): Ditto.
* tests/getopt-m4sh.at (_LT_AT_XSI_FUNC_EXTRACT): Rename to
_LT_AT_EXTENDED_SHELL_FUNC_EXTRACT.
(_LT_AT_EXTENDED_SHELL_FUNC_EXTRACT): Change regular expression to
match new replacable function decorator comments.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>