When I run Göran Weinholt's schjig <https://gitlab.com/weinholt/schjig>'s
`schjig.scm` against guile 3.0.8 I encounter the following error. Please
notice that I first switch on r6rs compatibility mode. I have no `.guile`
file. I did not see this listed on the R6RS incompatibilities
<https://www.gnu.org/software/guile/manual/html_node/R6RS-Incompatibilities.html>.
Is this a bug, either in guile or gmp?

```shell
$ guile
(install-r6rs!)
(load "schjig.scm")
...
(check (bitwise-rotate-bit-field 573972483446053417 1238 4006 -1627) =>
(quote 573972483446053417))
gmp: overflow in mpz type
Abort trap: 6
```

Best,

JBH