* strnlen.c: New file.
* configure.ac: Check for strnlen, add it to AC_LIBOBJ if it's not
present.
* Makefile.in: Rebuild dependencies.
(CFILES): Add strnlen.c.
(CONFIGURED_OFILES): Add ./strnlen.$(objext).
* configure, config.in, functions.texi: Rebuild.
* maint-tool: Accept .def files in the include directory.
From-SVN: r191432
