bug#10852: VPATH builds cannot recover from missing parser header

[Karl Berry]

Back on this bug from 2012,
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=10852

    ak> Also, why two "if"?
    sl> For the sake of "make -n": 

    * doc/automake.texi (Multiple Outputs): Split commands than
    reinvoke $(MAKE) to avoid file removals during dry runs.

I pushed Akim's patch.

Regarding the bigger issue mentioned in the middle:

> It basically boils down to whether the maintainer-src-tree should
> look like a fresh check-out, or a fresh tarball.  I think it should
> look like a tarball.

Personally I agree, but unless I'm misunderstanding, GNU packages have
moved quite in the other direction, aggressively minimizing the source
tree to be as much like a checkout as possible. E.g., there is no
ChangeLog file in Automake or most other git-based GNU packages.

I certainly have no appetite for attempting to change this, and it would
fly in the face of the established "git practice" of the last N years,
so I doubt such a policy would be warmly welcomed. So I'm closing this
bug. If I'm missing the point, can discuss further, of course. --best, karl.