strace requires gawk 4 but doesn't test for it

[DJ Delorie]

I recently tried to build strace on a system with gawk 3 (RHEL 6,
specifically).  Configure tested for gawk, found it, ran mpers.awk,
which failed... and silently ignored the failure.  The resulting
strace was built but didn't function correctly.

The core problem is that gawk 3 doesn't support [][] multi-dimensional
arrays at all.

Should gawk 3 be supported?  If not, shouldn't configure check for
multi-dimensional array support and fail if it's not found?