* ltdl.m4: Bump serial number.

* ltdl.m4: Bump serial number.
General reformat and tify up in line with Autoconf-2.50 support.
(AC_LTDL_FUNC_ARGZ): Test for system implementations of a
handful of argz API calls, the error_t type, and the argz.h
header.
* libltdl/configure.ac (AM_INIT_AUTOMAKE): Bump version number.
* libltdl/ltdl.c (rpl_argz_append, rpl_argz_create_sep.
rpl_argz_insert, rpl_rgz_next):  Fallback implementations of
the similarly named functions for machines that don;t use glibc.
(lt_dlrealloc):  New memory function pointer that can be set by
the client.  Defaults to rpl_realloc, which in turn uses only
lt_dlmalloc and lt_dlfree.
(LT_EMALLOC, LT_EREALLOC): Set internal out-of-memory error
inside the functions called by these new macros.  Simplified all
callers by removing explicit client error reporting.
(memmove):  Fallback implementation of overlap safe memory copy
function.
(tryall_dlopen):  Factorized common code into...
(tryall_dlopen_module): ...this new helper function.
(canonicalize_path):  Changed function signature to return success
or failure.  Updated all callers.
(foreachfile_callback):  Make use of argz API.
(LT_DLSTRLEN): Moved from here...
* libltdl/ltdl.h (LT_STRLEN): ...to here.  Updated all callers.
(lt_dlrealloc):  Declare new memory management handle.