Re: Coverage with make coverage-html is broken on latest Debian using lcov v2

I wrote:
> =?utf-8?Q?=C3=81lvaro?= Herrera <alvherre(at)kurilemu(dot)de> writes:
>> Handling this part with your 0001 seems reasonable to me. I think we
>> should backpatch that one.

> Agreed, and it doesn't look like that got done, so I'll go do it now.

Testing this locally, it initially didn't seem to be doing anything.
But that turns out to be because Red Hat has stuck with lcov 2.0-1,
which does not produce the "duplicate file" error. What it does do
is blindly read every foo.gcda file twice, resulting in counts twice
what they should be :-(. Now I wonder whether pre-2.0 lcov did the
same ... but I don't have an old executable laying about to test with.

I gather that coverage.postgresql.org is running a VPATH build,
because it shows some odd coverage counts as well as even ones.
That's impossible in an in-tree build with this bug, if I've
diagnosed it correctly.

Fix pushed.

regards, tom lane