Add module functions to convert from and to big integers.

* src/module-env-27.h: Add new module functions to convert big
integers.

* src/emacs-module.h.in (emacs_mpz): Define if GMP is available.

* src/emacs-module.c (module_extract_big_integer)
(module_make_big_integer): New functions.
(initialize_environment): Use them.

* test/data/emacs-module/mod-test.c (Fmod_test_double): New test
function.
(emacs_module_init): Define it.

* test/src/emacs-module-tests.el (mod-test-double): New unit test.

* doc/lispref/internals.texi (Module Values): Document new functions.

1 files changed, 4 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index fc9b828baa1..e861a372b17 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1913,6 +1913,10 @@ case.
 ** New module environment functions 'make_time' and 'extract_time' to
 convert between timespec structures and Emacs Lisp time values.
 
+** New module environment functions 'make_big_integer' and
+'extract_big_integer' to create and extract arbitrary-size integer
+values.
+
 
 * Changes in Emacs 27.1 on Non-Free Operating Systems