In http://lists.gnu.org/archive/html/bug-autoconf/2015-12/msg00000.html
Pavel Raiskup reports that ${1+"$@"} runs afoul of a bug in /bin/sh
(derived from ksh 93t+ 2010-03-05). ${1+"$@"} works around an ancient
bug in long-dead shells, so remove the workaround.
* admin/check-doc-strings, configure.ac, lib-src/rcs2log:
Use plain "$@" rather than ${1+"$@"}.