Support .dylib suffix for modules on macOS (Bug#36226).

On macOS, shared libraries typically have the suffix .dylib.  This
commit switches the module suffix to .dylib on Darwin to account for
that.  To also support the .so suffix, introduce the concept of a
secondary module suffix.

* configure.ac: Switch MODULES_SUFFIX to .dylib for Darwin, introduce
MODULES_SECONDARY_SUFFIX.

* src/lread.c (Fload, syms_of_lread): Also use
MODULES_SECONDARY_SUFFIX if defined.

* test/src/emacs-module-tests.el (module-darwin-secondary-suffix): New
unit test.

1 files changed, 18 insertions, 0 deletions

diff --git a/test/src/emacs-module-tests.el b/test/src/emacs-module-tests.el
index 18766081c0a..322500ff604 100644
--- a/test/src/emacs-module-tests.el
+++ b/test/src/emacs-module-tests.el
@@ -384,4 +384,22 @@ Interactively, you can try hitting \\[keyboard-quit] to quit."
     (ert-info ((format "input: %d" input))
       (should (= (mod-test-double input) (* 2 input))))))
 
+(ert-deftest module-darwin-secondary-suffix ()
+  "Check that on Darwin, both .so and .dylib suffixes work.
+See Bug#36226."
+  (skip-unless (eq system-type 'darwin))
+  (should (member ".dylib" load-suffixes))
+  (should (member ".so" load-suffixes))
+  ;; Preserve the old `load-history'.  This is needed for some of the
+  ;; other unit tests that indirectly rely on `load-history'.
+  (let ((load-history load-history)
+        (dylib (concat mod-test-file ".dylib"))
+        (so (concat mod-test-file ".so")))
+    (should (file-regular-p dylib))
+    (should-not (file-exists-p so))
+    (add-name-to-file dylib so)
+    (unwind-protect
+        (load so nil nil :nosuffix :must-suffix)
+      (delete-file so))))
+
 ;;; emacs-module-tests.el ends here