Allow creating unibyte strings from Emacs modules

* doc/lispref/internals.texi (Module Values): Document
make_unibyte_string (bug#34873).

* src/emacs-module.c (module_make_unibyte_string): New function.
(initialize_environment): Export it.

* src/module-env-25.h: Define it.

* test/data/emacs-module/mod-test.c (Fmod_test_return_unibyte):
Test it.

* test/src/emacs-module-tests.el (module/unibyte): Test it.

1 files changed, 6 insertions, 0 deletions

diff --git a/test/src/emacs-module-tests.el b/test/src/emacs-module-tests.el
index 1eebb418cf3..621229c62aa 100644
--- a/test/src/emacs-module-tests.el
+++ b/test/src/emacs-module-tests.el
@@ -500,4 +500,10 @@ See Bug#36226."
   (should (eq (mod-test-identity 123) 123))
   (should-not (call-interactively #'mod-test-identity)))
 
+(ert-deftest module/unibyte ()
+  (let ((result (mod-test-return-unibyte)))
+    (should (stringp result))
+    (should (not (multibyte-string-p (mod-test-return-unibyte))))
+    (should (equal result "foo\x00zot"))))
+
 ;;; emacs-module-tests.el ends here