Add tests and smoketest

Author: ychin

.github/workflows/macvim-buildtest.yaml

@@ -284,6 +284,11 @@ jobs:
             echo 'Found external dynamic linkage!'; false
           fi
 
+          # Make sure we are not using system iconv, which has been buggy since macOS 14.
+          if otool -L ${VIM_BIN} | grep '^\s*/usr/lib/libiconv'; then
+            echo 'Using system iconv! We should be linking against GNU iconv instead.'; false
+          fi
+
           # Make sure that --disable-sparkle flag will properly exclude all references to Sparkle symbols. This is
           # necessary because we still use weak linking to Sparkle when that flag is set and so references to Sparkle
           # wouldn't fail the build (we just remove Sparkle.framework from the built app after the fact).

src/testdir/test_macvim.vim

@@ -35,6 +35,7 @@ func Test_macvim_options_commands_exist()
     call assert_true(has('clientserver'), 'Missing feature "clientserver"')
     call assert_true(has('clipboard'), 'Missing feature "clipboard"')
     call assert_true(has('clipboard_working'), 'Missing feature "clipboard_working"')
+    call assert_true(has('iconv'), 'Missing feature "iconv"')
     call assert_true(has('sound'), 'Missing feature "sound"')
     call assert_true(has('terminal'), 'Missing feature "terminal"')
     call assert_true(has('xim'), 'Missing feature "xim"')