incorrect output and segfaults from sprintf with %*d (PR#13667)

Yes, the documentation will also have to be amended, but apart
from that, would people see a big problem with the "8192" limit
which now is suddenly of greater importance
{{as I said all along; ?hence my question to Wacek (and the
?R-develers) ?if anybody found that limit too low}}

I haven't been following all this but in working with strings for
the gsubfn package my own usage of the package was primarily
for small strings but then I discovered that others wanted to use
it for much larger strings of 25,000 characters, say, and it was
necessary to raise the limits (and there are also performance
implications which could be addressed too). I don't know what
the situation is particularly here but cases where
very large strings can be used include linguistic analysis and
computer generated R code.