Factor out the bottom portability layer from ltdl. Code in this
layer has global symbols renamed by lt__pre89.h, and may not
refer to any symbols except those provided by the system libraries
or other code in the portability layer:
* libltdl/lt__pre89.h: New file. Rename all the symbols from
LTLIBOBJS into the lt__ namespace so that they don't clash with
other libraries.
* libltdl/ltdl.c (rpl_memcpy, rpl_memmove, rpl_strchr, rpl_strcmp)
(rpl_strrchr): Moved from here...
* libltdl/memcpy.c (memcpy): ...to here, and fixed void *
dereference bug...
* libltdl/memmove.c (memmove): ...to here, and fixed void *
dereference bug...
* libltdl/strchr.c (strchr): ...to here...
* libltdl/strcmp.c (strcmp): ...here...
* libltdl/strrchr.c (strrchr): ...and here.
* libltdl/Makefile.am (libltdl_la_SOURCES): Add lt__pre89.h.
(libltdl_la_LIBADD, libltdlc_la_LIBADD): Add $(LTLIBOBJS).
(ltdldata_DATA): Add replacement sources files.
* m4/ltdl.m4 (AC_LIB_LTDL): Do careful config.h and LTLIBOBJ
setting for missing pre89 functions.