small regression in autoconf-2.64 AC_CHECK_MEMBERS

[Bruno Haible]

The description of the macro corresponding to an AC_CHECK_MEMBERS
invocation, stored in config.h.in by 'autoheader', is wrong in autoconf-2.64.
It was correct in autoconf-2.63.

How to reproduce:

$ cat > configure.ac <<EOF
AC_INIT
AC_CONFIG_HEADER([config.h])
AC_PROG_CC
AC_CHECK_MEMBERS([struct sigaction.sa_sigaction], , , [[#include <signal.h>]])
AC_OUTPUT
EOF
$ /arch/x86-linux/gnu-inst-autoconf/2.64/bin/autoheader
$ grep member config.h.in 
/* Define to 1 if `struct sigaction' is a member of `sa_sigaction'. */
$ /arch/x86-linux/gnu-inst-autoconf/2.63/bin/autoheader
$ grep member config.h.in 
/* Define to 1 if `sa_sigaction' is member of `struct sigaction'. */

Either the two `...' strings needs to be swapped, or "is a member of"
needs to be changed into "has a member named".

Bruno