Add CI / test checks to make sure we don't accidentally lose features

Add CI test to confirm desired Vim features like +sound / etc exist.

Smoketest also checks for libsodium now by trying to set xchacha20
cryptmethod which can only succeed if sodium is enabled. Also make sure
it's actually checking the scripting language bindings are working
properly. Previously for some reason it wasn't checking the print
results.

Author: ychin

.github/workflows/ci-macvim.yaml

@@ -251,15 +251,18 @@ jobs:
           }
 
           # Smoketest scripting languages
-          macvim_excmd -c 'lua print("Test")'
-          macvim_excmd -c 'perl VIM::Msg("Test")'
-          macvim_excmd -c 'py print "Test"'
-          macvim_excmd -c 'py3 print("Test")'
-          macvim_excmd -c 'ruby puts("Test")'
+          macvim_excmd -c 'lua print("Test")'     | grep Test
+          macvim_excmd -c 'perl VIM::Msg("Test")' | grep Test
+          macvim_excmd -c 'py print "Test"'       | grep Test
+          macvim_excmd -c 'py3 print("Test")'     | grep Test
+          macvim_excmd -c 'ruby puts("Test")'     | grep Test
 
           # Check that localized messages work by printing ':version' and checking against localized word
           macvim_excmd -c 'lang es_ES' -c 'version' | grep Enlazado
 
+          # Check that libsodium is working
+          macvim_excmd -c 'set cryptmethod=xchacha20'
+
           # Make sure there isn't any dynamic linkage to third-party dependencies in the built binary, as we should only use
           # static linkage to avoid dependency hell. Test that all those dylib's are in /usr/lib which is bundled with macOS and not third-party.
           if otool -L ${VIM_BIN} | grep '\.dylib\s' | grep -v '^\s*/usr/lib/'; then

src/testdir/test_macvim.vim

@@ -19,13 +19,21 @@ func Test_macvim_options_commands()
     call assert_true(exists(':macaction'), 'Missing command "macaction"')
     call assert_true(exists(':macmenu'), 'Missing command "macmenu"')
 
+    call assert_true(exists('*showdefinition'), 'Missing function "showdefinition"')
+
     call assert_true(exists('##OSAppearanceChanged'), 'Missing autocmd event "OSAppearanceChanged"')
 
     call assert_true(has('fullscreen'), 'Missing feature "fullscreen"')
     call assert_true(has('gui_macvim'), 'Missing feature "gui_macvim"')
     call assert_true(has('odbeditor'), 'Missing feature "odbeditor"')
     call assert_true(has('touchbar'), 'Missing feature "touchbar"')
     call assert_true(has('transparency'), 'Missing feature "transparency"')
+
+    " Vim system-specific features that we expect to be on in macOS
+    call assert_true(has('clipboard'), 'Missing feature "clipboard"')
+    call assert_true(has('sound'), 'Missing feature "sound"')
+    call assert_true(has('terminal'), 'Missing feature "terminal"')
+    call assert_true(has('xim'), 'Missing feature "xim"')
 endfunc
 
 " Test that Cmd-key and touch pad mappings are working (this doesn't actually