bootstrapping r118945 failed

[Paul Richard Thomas]

Dear All,

I can confirm this at r118968.  I am blowed if I can see what is wrong
with matmul itself - I tried reverting libgfortran to r118947, which
was just before the last modification to matmul; with the same result.
 I note that there is a PR for this.

I am now reverting the whole compiler to before the other reported
boot failures.  However, I seem to have lost the opportunity to do the
commits that I had intended - they will just have to wait ~10 days.
Unless I get up a couple of hours early tomorrow morning:)

Grrrr!

Paul