* lib/regex.h (_Restrict_): Renamed from __restrict, to avoid

* lib/regex.h (_Restrict_): Renamed from __restrict, to avoid
a circularity problem with HP-UX ia64 reported by Bob Proulx in
<http://lists.gnu.org/archive/html/bug-gnulib/2007-01/msg00394.html>.
All uses changed.
(_Restrict_arr_): Renamed from __restrict_arr, for similar reasons.
All uses changed.
* lib/regcomp.c, lib/regexec.c: Change all uses from __restrict
to _Restrict_.
* lib/regexec.c (regexec): Declare pmatch with _Restrict_arr_, so that
the parameter matches the prototype.